diff --git a/src/bin/topola-sdl2-demo/main.rs b/src/bin/topola-sdl2-demo/main.rs
index 6ba516f..50957c2 100644
--- a/src/bin/topola-sdl2-demo/main.rs
+++ b/src/bin/topola-sdl2-demo/main.rs
@@ -56,7 +56,7 @@ impl RulesTrait for SimpleRules {
     fn clearance(&self, conditions1: &Conditions, conditions2: &Conditions) -> f64 {
         *self
             .net_clearances
-            .get(&(conditions1.net, conditions2.net))
+            .get(&(conditions1.maybe_net, conditions2.maybe_net))
             .unwrap_or(&10.0)
     }
 
diff --git a/src/draw.rs b/src/draw.rs
index 59c81e5..66e7a61 100644
--- a/src/draw.rs
+++ b/src/draw.rs
@@ -6,7 +6,7 @@ use crate::{
     drawing::{
         bend::{BendIndex, LooseBendWeight},
         dot::{DotIndex, FixedDotIndex, LooseDotIndex, LooseDotWeight},
-        graph::{GetLayer, GetNet, MakePrimitive},
+        graph::{GetLayer, GetMaybeNet, MakePrimitive},
         guide::{Guide, Head, HeadTrait, SegbendHead},
         primitive::GetOtherJoint,
         rules::RulesTrait,
@@ -59,17 +59,33 @@ impl<'a, R: RulesTrait> Draw<'a, R> {
             .extend_head(head, tangent.start_point())
             .map_err(|err| DrawException::CannotFinishIn(into, err.into()))?;
         let layer = head.face().primitive(self.layout.layout()).layer();
-        let net = head.face().primitive(self.layout.layout()).net();
+        let maybe_net = head.face().primitive(self.layout.layout()).maybe_net();
 
         match head.face() {
             DotIndex::Fixed(dot) => {
                 self.layout
-                    .add_lone_loose_seg(dot, into.into(), LoneLooseSegWeight { width, layer, net })
+                    .add_lone_loose_seg(
+                        dot,
+                        into.into(),
+                        LoneLooseSegWeight {
+                            width,
+                            layer,
+                            maybe_net,
+                        },
+                    )
                     .map_err(|err| DrawException::CannotFinishIn(into, err.into()))?;
             }
             DotIndex::Loose(dot) => {
                 self.layout
-                    .add_seq_loose_seg(into.into(), dot, SeqLooseSegWeight { width, layer, net })
+                    .add_seq_loose_seg(
+                        into.into(),
+                        dot,
+                        SeqLooseSegWeight {
+                            width,
+                            layer,
+                            maybe_net,
+                        },
+                    )
                     .map_err(|err| DrawException::CannotFinishIn(into, err.into()))?;
             }
         }
@@ -204,7 +220,7 @@ impl<'a, R: RulesTrait> Draw<'a, R> {
         offset: f64,
     ) -> Result<SegbendHead, LayoutException> {
         let layer = head.face().primitive(self.layout.layout()).layer();
-        let net = head.face().primitive(self.layout.layout()).net();
+        let maybe_net = head.face().primitive(self.layout.layout()).maybe_net();
         let segbend = self.layout.insert_segbend(
             head.face(),
             around,
@@ -214,14 +230,18 @@ impl<'a, R: RulesTrait> Draw<'a, R> {
                     r: width / 2.0,
                 },
                 layer,
-                net,
+                maybe_net,
+            },
+            SeqLooseSegWeight {
+                width,
+                layer,
+                maybe_net,
             },
-            SeqLooseSegWeight { width, layer, net },
             LooseBendWeight {
                 width,
                 offset,
                 layer,
-                net,
+                maybe_net,
             },
             cw,
         )?;
diff --git a/src/drawing/bend.rs b/src/drawing/bend.rs
index 90be194..72c57b7 100644
--- a/src/drawing/bend.rs
+++ b/src/drawing/bend.rs
@@ -2,7 +2,7 @@ use enum_dispatch::enum_dispatch;
 
 use crate::{
     drawing::{
-        graph::{GeometryIndex, GeometryWeight, GetLayer, GetNet, MakePrimitive, Retag},
+        graph::{GeometryIndex, GeometryWeight, GetLayer, GetMaybeNet, MakePrimitive, Retag},
         primitive::{GenericPrimitive, Primitive},
         rules::RulesTrait,
         Drawing,
@@ -76,7 +76,7 @@ pub struct FixedBendWeight {
     pub width: f64,
     pub offset: f64,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_fixed_weight!(FixedBendWeight, FixedBend, FixedBendIndex);
@@ -105,7 +105,7 @@ pub struct LooseBendWeight {
     pub width: f64,
     pub offset: f64,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl GetOffset for LooseBendWeight {
diff --git a/src/drawing/dot.rs b/src/drawing/dot.rs
index 9f6231f..8ecefcf 100644
--- a/src/drawing/dot.rs
+++ b/src/drawing/dot.rs
@@ -5,7 +5,7 @@ use petgraph::stable_graph::NodeIndex;
 
 use crate::{
     drawing::{
-        graph::{GeometryIndex, GeometryWeight, GetLayer, GetNet, MakePrimitive, Retag},
+        graph::{GeometryIndex, GeometryWeight, GetLayer, GetMaybeNet, MakePrimitive, Retag},
         primitive::{GenericPrimitive, Primitive},
         rules::RulesTrait,
         Drawing,
@@ -77,7 +77,7 @@ impl DotWeightTrait<GeometryWeight> for DotWeight {}
 pub struct FixedDotWeight {
     pub circle: Circle,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_fixed_weight!(FixedDotWeight, FixedDot, FixedDotIndex);
@@ -105,7 +105,7 @@ impl GetWidth for FixedDotWeight {
 pub struct LooseDotWeight {
     pub circle: Circle,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_loose_weight!(LooseDotWeight, LooseDot, LooseDotIndex);
diff --git a/src/drawing/drawing.rs b/src/drawing/drawing.rs
index c844231..283d41a 100644
--- a/src/drawing/drawing.rs
+++ b/src/drawing/drawing.rs
@@ -12,7 +12,7 @@ use super::segbend::Segbend;
 use crate::drawing::bend::BendIndex;
 use crate::drawing::collect::Collect;
 use crate::drawing::dot::DotWeight;
-use crate::drawing::graph::GetNet;
+use crate::drawing::graph::GetMaybeNet;
 use crate::drawing::guide::Guide;
 use crate::drawing::primitive::GetLimbs;
 use crate::drawing::rules::GetConditions;
@@ -63,7 +63,7 @@ pub struct Collision(pub Shape, pub GeometryIndex);
 
 #[derive(Error, Debug, Clone, Copy)]
 #[error("{1:?} is already connected to net {0}")]
-pub struct AlreadyConnected(pub i64, pub GeometryIndex);
+pub struct AlreadyConnected(pub usize, pub GeometryIndex);
 
 #[derive(Debug)]
 pub struct Drawing<R: RulesTrait> {
@@ -501,13 +501,19 @@ impl<R: RulesTrait> Drawing<R> {
     ) -> Result<LooseBendIndex, LayoutException> {
         // It makes no sense to wrap something around or under one of its connectables.
         //
-        if weight.net == around.primitive(self).net() {
-            return Err(AlreadyConnected(weight.net, around.into()).into());
-        }
-        //
-        if let Some(wraparound) = self.wraparoundable(around).wraparound() {
-            if weight.net == wraparound.primitive(self).net() {
-                return Err(AlreadyConnected(weight.net, wraparound.into()).into());
+        if let Some(net) = weight.maybe_net {
+            if let Some(around_net) = around.primitive(self).maybe_net() {
+                if net == around_net {
+                    return Err(AlreadyConnected(net, around.into()).into());
+                }
+            }
+            //
+            if let Some(wraparound) = self.wraparoundable(around).wraparound() {
+                if let Some(wraparound_net) = wraparound.primitive(self).maybe_net() {
+                    if net == wraparound_net {
+                        return Err(AlreadyConnected(net, wraparound.into()).into());
+                    }
+                }
             }
         }
 
@@ -714,10 +720,12 @@ impl<R: RulesTrait> Drawing<R> {
         node: GeometryIndex,
         maybe_except: Option<&[GeometryIndex]>,
     ) -> Option<Infringement> {
-        let limiting_shape = node
-            .primitive(self)
-            .shape()
-            .inflate(self.rules.largest_clearance(node.primitive(self).net()));
+        let limiting_shape = node.primitive(self).shape().inflate(
+            node.primitive(self)
+                .maybe_net()
+                .and_then(|net| Some(self.rules.largest_clearance(Some(net))))
+                .unwrap_or(0.0),
+        );
         let mut inflated_shape = limiting_shape; // Unused temporary value just for initialization.
         let conditions = node.primitive(self).conditions();
 
@@ -760,10 +768,14 @@ impl<R: RulesTrait> Drawing<R> {
     #[debug_ensures(self.geometry_with_rtree.graph().node_count() == old(self.geometry_with_rtree.graph().node_count()))]
     #[debug_ensures(self.geometry_with_rtree.graph().edge_count() == old(self.geometry_with_rtree.graph().edge_count()))]
     fn are_connectable(&self, node1: GeometryIndex, node2: GeometryIndex) -> bool {
-        let node1_net = node1.primitive(self).net();
-        let node2_net = node2.primitive(self).net();
-
-        (node1_net == node2_net) || node1_net == -1 || node2_net == -2
+        if let (Some(node1_net_id), Some(node2_net_id)) = (
+            node1.primitive(self).maybe_net(),
+            node2.primitive(self).maybe_net(),
+        ) {
+            node1_net_id == node2_net_id
+        } else {
+            true
+        }
     }
 }
 
diff --git a/src/drawing/graph.rs b/src/drawing/graph.rs
index 15a7577..4e5b9b0 100644
--- a/src/drawing/graph.rs
+++ b/src/drawing/graph.rs
@@ -26,8 +26,8 @@ pub trait GetLayer {
 }
 
 #[enum_dispatch]
-pub trait GetNet {
-    fn net(&self) -> i64;
+pub trait GetMaybeNet {
+    fn maybe_net(&self) -> Option<usize>;
 }
 
 #[enum_dispatch]
@@ -49,9 +49,9 @@ macro_rules! impl_weight {
             }
         }
 
-        impl<'a> GetNet for $weight_struct {
-            fn net(&self) -> i64 {
-                self.net
+        impl<'a> GetMaybeNet for $weight_struct {
+            fn maybe_net(&self) -> Option<usize> {
+                self.maybe_net
             }
         }
 
diff --git a/src/drawing/primitive.rs b/src/drawing/primitive.rs
index 3ec7b2a..7512dd8 100644
--- a/src/drawing/primitive.rs
+++ b/src/drawing/primitive.rs
@@ -4,7 +4,7 @@ use petgraph::stable_graph::NodeIndex;
 use crate::drawing::{
     bend::{BendIndex, FixedBendWeight, LooseBendIndex, LooseBendWeight},
     dot::{DotIndex, DotWeight, FixedDotIndex, FixedDotWeight, LooseDotIndex, LooseDotWeight},
-    graph::{GeometryIndex, GeometryWeight, GetLayer, GetNet, Retag},
+    graph::{GeometryIndex, GeometryWeight, GetLayer, GetMaybeNet, Retag},
     loose::LooseIndex,
     rules::{Conditions, GetConditions, RulesTrait},
     seg::{
@@ -130,9 +130,9 @@ macro_rules! impl_primitive {
             }
         }
 
-        impl<'a, R: RulesTrait> GetNet for $primitive_struct<'a, R> {
-            fn net(&self) -> i64 {
-                self.weight().net()
+        impl<'a, R: RulesTrait> GetMaybeNet for $primitive_struct<'a, R> {
+            fn maybe_net(&self) -> Option<usize> {
+                self.weight().maybe_net()
             }
         }
     };
@@ -152,7 +152,7 @@ macro_rules! impl_loose_primitive {
 
 #[enum_dispatch(
     GetLayer,
-    GetNet,
+    GetMaybeNet,
     GetWidth,
     GetLayout,
     MakeShape,
@@ -223,13 +223,13 @@ where
 
 impl<'a, W, R: RulesTrait> GetConditions for GenericPrimitive<'a, W, R>
 where
-    GenericPrimitive<'a, W, R>: GetNet,
+    GenericPrimitive<'a, W, R>: GetMaybeNet,
 {
     fn conditions(&self) -> Conditions {
         Conditions {
-            net: self.net(),
-            region: Some("A".to_string()),
-            layer: Some("F.Cu".to_string()),
+            maybe_net: self.maybe_net(),
+            maybe_region: Some("A".to_string()),
+            maybe_layer: Some("F.Cu".to_string()),
         }
     }
 }
diff --git a/src/drawing/rules.rs b/src/drawing/rules.rs
index 59283a8..ecc2c4b 100644
--- a/src/drawing/rules.rs
+++ b/src/drawing/rules.rs
@@ -9,12 +9,12 @@ pub trait GetConditions {
 
 #[derive(Debug, Default)]
 pub struct Conditions {
-    pub net: i64,
-    pub region: Option<String>,
-    pub layer: Option<String>,
+    pub maybe_net: Option<usize>,
+    pub maybe_region: Option<String>,
+    pub maybe_layer: Option<String>,
 }
 
 pub trait RulesTrait {
     fn clearance(&self, conditions1: &Conditions, conditions2: &Conditions) -> f64;
-    fn largest_clearance(&self, net: i64) -> f64;
+    fn largest_clearance(&self, net: Option<usize>) -> f64;
 }
diff --git a/src/drawing/seg.rs b/src/drawing/seg.rs
index 31f499f..705a8e9 100644
--- a/src/drawing/seg.rs
+++ b/src/drawing/seg.rs
@@ -2,7 +2,7 @@ use enum_dispatch::enum_dispatch;
 
 use crate::{
     drawing::{
-        graph::{GeometryIndex, GeometryWeight, GetLayer, GetNet, MakePrimitive, Retag},
+        graph::{GeometryIndex, GeometryWeight, GetLayer, GetMaybeNet, MakePrimitive, Retag},
         primitive::{GenericPrimitive, Primitive},
         rules::RulesTrait,
         Drawing,
@@ -81,7 +81,7 @@ impl SegWeightTrait<GeometryWeight> for SegWeight {}
 pub struct FixedSegWeight {
     pub width: f64,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_fixed_weight!(FixedSegWeight, FixedSeg, FixedSegIndex);
@@ -97,7 +97,7 @@ impl GetWidth for FixedSegWeight {
 pub struct LoneLooseSegWeight {
     pub width: f64,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_loose_weight!(LoneLooseSegWeight, LoneLooseSeg, LoneLooseSegIndex);
@@ -113,7 +113,7 @@ impl GetWidth for LoneLooseSegWeight {
 pub struct SeqLooseSegWeight {
     pub width: f64,
     pub layer: u64,
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
 impl_loose_weight!(SeqLooseSegWeight, SeqLooseSeg, SeqLooseSegIndex);
diff --git a/src/dsn/design.rs b/src/dsn/design.rs
index 76e7743..34f03c6 100644
--- a/src/dsn/design.rs
+++ b/src/dsn/design.rs
@@ -46,7 +46,7 @@ impl DsnDesign {
         let mut layout = Drawing::new(rules);
 
         // mapping of pin id -> net id prepared for adding pins
-        let pin_nets = HashMap::<String, i64>::from_iter(
+        let pin_nets = HashMap::<String, usize>::from_iter(
             self.pcb
                 .network
                 .net_vec
@@ -103,7 +103,7 @@ impl DsnDesign {
                                     pin.rotate.unwrap_or(0.0) as f64,
                                     circle.diameter as f64 / 2.0,
                                     layer as u64,
-                                    *net_id as i64,
+                                    *net_id,
                                 )
                             }
                             Shape::Rect(rect) => {
@@ -124,7 +124,7 @@ impl DsnDesign {
                                     rect.x2 as f64,
                                     rect.y2 as f64,
                                     layer as u64,
-                                    *net_id as i64,
+                                    *net_id,
                                 )
                             }
                             Shape::Path(path) => {
@@ -143,7 +143,7 @@ impl DsnDesign {
                                     &path.coord_vec,
                                     path.width as f64,
                                     layer as u64,
-                                    *net_id as i64,
+                                    *net_id,
                                 )
                             }
                             Shape::Polygon(polygon) => {
@@ -162,7 +162,7 @@ impl DsnDesign {
                                     &polygon.coord_vec,
                                     polygon.width as f64,
                                     layer as u64,
-                                    *net_id as i64,
+                                    *net_id,
                                 )
                             }
                         };
@@ -200,7 +200,7 @@ impl DsnDesign {
                             0.0,
                             circle.diameter as f64 / 2.0,
                             layer as u64,
-                            net_id as i64,
+                            net_id,
                         )
                     }
                     Shape::Rect(rect) => {
@@ -221,7 +221,7 @@ impl DsnDesign {
                             rect.x2 as f64,
                             rect.y2 as f64,
                             layer as u64,
-                            net_id as i64,
+                            net_id,
                         )
                     }
                     Shape::Path(path) => {
@@ -240,7 +240,7 @@ impl DsnDesign {
                             &path.coord_vec,
                             path.width as f64,
                             layer as u64,
-                            net_id as i64,
+                            net_id,
                         )
                     }
                     Shape::Polygon(polygon) => {
@@ -259,7 +259,7 @@ impl DsnDesign {
                             &polygon.coord_vec,
                             polygon.width as f64,
                             layer as u64,
-                            net_id as i64,
+                            net_id,
                         )
                     }
                 };
@@ -279,7 +279,7 @@ impl DsnDesign {
                 &wire.path.coord_vec,
                 wire.path.width as f64,
                 layer_id as u64,
-                net_id as i64,
+                net_id,
             );
         }
 
@@ -309,7 +309,7 @@ impl DsnDesign {
         pin_rot: f64,
         r: f64,
         layer: u64,
-        net: i64,
+        net: usize,
     ) {
         let circle = Circle {
             pos: Self::pos(place_pos, place_rot, pin_pos, pin_rot, 0.0, 0.0),
@@ -317,7 +317,11 @@ impl DsnDesign {
         };
 
         drawing
-            .add_fixed_dot(FixedDotWeight { circle, layer, net })
+            .add_fixed_dot(FixedDotWeight {
+                circle,
+                layer,
+                maybe_net: Some(net),
+            })
             .unwrap();
     }
 
@@ -332,7 +336,7 @@ impl DsnDesign {
         x2: f64,
         y2: f64,
         layer: u64,
-        net: i64,
+        net: usize,
     ) {
         // Corners.
         let dot_1_1 = drawing
@@ -342,7 +346,7 @@ impl DsnDesign {
                     r: 0.5,
                 },
                 layer,
-                net,
+                maybe_net: Some(net),
             })
             .unwrap();
         let dot_2_1 = drawing
@@ -352,7 +356,7 @@ impl DsnDesign {
                     r: 0.5,
                 },
                 layer,
-                net,
+                maybe_net: Some(net),
             })
             .unwrap();
         let dot_2_2 = drawing
@@ -362,7 +366,7 @@ impl DsnDesign {
                     r: 0.5,
                 },
                 layer,
-                net,
+                maybe_net: Some(net),
             })
             .unwrap();
         let dot_1_2 = drawing
@@ -372,7 +376,7 @@ impl DsnDesign {
                     r: 0.5,
                 },
                 layer,
-                net,
+                maybe_net: Some(net),
             })
             .unwrap();
         // Sides.
@@ -383,7 +387,7 @@ impl DsnDesign {
                 FixedSegWeight {
                     width: 1.0,
                     layer,
-                    net,
+                    maybe_net: Some(net),
                 },
             )
             .unwrap();
@@ -394,7 +398,7 @@ impl DsnDesign {
                 FixedSegWeight {
                     width: 1.0,
                     layer,
-                    net,
+                    maybe_net: Some(net),
                 },
             )
             .unwrap();
@@ -405,7 +409,7 @@ impl DsnDesign {
                 FixedSegWeight {
                     width: 1.0,
                     layer,
-                    net,
+                    maybe_net: Some(net),
                 },
             )
             .unwrap();
@@ -416,7 +420,7 @@ impl DsnDesign {
                 FixedSegWeight {
                     width: 1.0,
                     layer,
-                    net,
+                    maybe_net: Some(net),
                 },
             )
             .unwrap();
@@ -431,7 +435,7 @@ impl DsnDesign {
         coords: &Vec<structure::Point>,
         width: f64,
         layer: u64,
-        net: i64,
+        net: usize,
     ) {
         // add the first coordinate in the wire path as a dot and save its index
         let mut prev_index = drawing
@@ -448,7 +452,7 @@ impl DsnDesign {
                     r: width / 2.0,
                 },
                 layer,
-                net,
+                maybe_net: Some(net),
             })
             .unwrap();
 
@@ -469,13 +473,21 @@ impl DsnDesign {
                         r: width / 2.0,
                     },
                     layer,
-                    net,
+                    maybe_net: Some(net),
                 })
                 .unwrap();
 
             // add a seg between the current and previous coords
             let _ = drawing
-                .add_fixed_seg(prev_index, index, FixedSegWeight { width, layer, net })
+                .add_fixed_seg(
+                    prev_index,
+                    index,
+                    FixedSegWeight {
+                        width,
+                        layer,
+                        maybe_net: Some(net),
+                    },
+                )
                 .unwrap();
 
             prev_index = index;
diff --git a/src/dsn/rules.rs b/src/dsn/rules.rs
index 2d36a4f..c7516db 100644
--- a/src/dsn/rules.rs
+++ b/src/dsn/rules.rs
@@ -28,9 +28,9 @@ pub struct DsnRules {
     // layer names -> layer IDs for Layout
     pub layer_ids: HashMap<String, u64>,
     // net names -> net IDs for Layout
-    pub net_ids: HashMap<String, i64>,
+    pub net_ids: HashMap<String, usize>,
     // net ID -> net class
-    net_id_classes: HashMap<i64, String>,
+    net_id_classes: HashMap<usize, String>,
 }
 
 impl DsnRules {
@@ -49,7 +49,7 @@ impl DsnRules {
                 .iter()
                 .flat_map(|class| &class.net_vec)
                 .enumerate()
-                .map(|(id, net)| (net.clone(), id as i64)),
+                .map(|(id, net)| (net.clone(), id)),
         );
 
         let mut net_id_classes = HashMap::new();
@@ -75,7 +75,7 @@ impl DsnRules {
         }
     }
 
-    pub fn get_rule(&self, net: i64) -> &DsnRule {
+    pub fn get_rule(&self, net: usize) -> &DsnRule {
         if let Some(netclass) = self.net_id_classes.get(&net) {
             self.class_rules
                 .get(netclass)
@@ -88,8 +88,12 @@ impl DsnRules {
 
 impl RulesTrait for DsnRules {
     fn clearance(&self, conditions1: &Conditions, conditions2: &Conditions) -> f64 {
-        let clr1 = self.get_rule(conditions1.net).clearance;
-        let clr2 = self.get_rule(conditions2.net).clearance;
+        let (Some(net1), Some(net2)) = (conditions1.maybe_net, conditions2.maybe_net) else {
+            return 0.0;
+        };
+
+        let clr1 = self.get_rule(net1).clearance;
+        let clr2 = self.get_rule(net2).clearance;
 
         if clr1 > clr2 {
             clr1
@@ -98,7 +102,7 @@ impl RulesTrait for DsnRules {
         }
     }
 
-    fn largest_clearance(&self, _net: i64) -> f64 {
+    fn largest_clearance(&self, maybe_net: Option<usize>) -> f64 {
         let mut largest: f64 = 0.0;
 
         for (class, rule) in &self.class_rules {
diff --git a/src/layout/connectivity.rs b/src/layout/connectivity.rs
index 61d3d27..674528a 100644
--- a/src/layout/connectivity.rs
+++ b/src/layout/connectivity.rs
@@ -2,7 +2,7 @@ use enum_dispatch::enum_dispatch;
 use petgraph::stable_graph::StableDiGraph;
 
 use crate::{
-    drawing::{dot::FixedDotIndex, graph::GetNet, primitive::Primitive, rules::RulesTrait},
+    drawing::{dot::FixedDotIndex, graph::GetMaybeNet, primitive::Primitive, rules::RulesTrait},
     graph::GenericIndex,
 };
 
@@ -16,12 +16,12 @@ pub enum ConnectivityWeight {
 
 #[derive(Debug, Clone, Copy)]
 pub struct ContinentWeight {
-    pub net: i64,
+    pub maybe_net: Option<usize>,
 }
 
-impl GetNet for ContinentWeight {
-    fn net(&self) -> i64 {
-        self.net
+impl GetMaybeNet for ContinentWeight {
+    fn maybe_net(&self) -> Option<usize> {
+        self.maybe_net
     }
 }
 
diff --git a/src/tracer.rs b/src/tracer.rs
index ecaa4cc..bb6ae9b 100644
--- a/src/tracer.rs
+++ b/src/tracer.rs
@@ -5,7 +5,7 @@ use crate::{
     drawing::{
         bend::LooseBendIndex,
         dot::FixedDotIndex,
-        graph::{GetNet, MakePrimitive},
+        graph::{GetMaybeNet, MakePrimitive},
         guide::{BareHead, Head, HeadTrait, SegbendHead},
         rules::RulesTrait,
     },