diff --git a/layouts/contract.go b/layouts/contract.go
index f92b74c..8550882 100644
--- a/layouts/contract.go
+++ b/layouts/contract.go
@@ -3,6 +3,8 @@ package layouts
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = ContractVertical
+
 // Contract is a layout that arranges boxes in a simple row or column according
 // to their minimum sizes.
 type Contract bool
diff --git a/layouts/cut.go b/layouts/cut.go
index 3ee9d73..4ecd09b 100644
--- a/layouts/cut.go
+++ b/layouts/cut.go
@@ -3,6 +3,8 @@ package layouts
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = new(cut)
+
 // Cut is a layout that can be divided into smaller and smaller sections.
 type Cut struct {
 	branches []*Cut
diff --git a/layouts/flow.go b/layouts/flow.go
index 3790dd3..e6acd27 100644
--- a/layouts/flow.go
+++ b/layouts/flow.go
@@ -3,6 +3,8 @@ package layouts
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = FlowVertical
+
 // Flow is a grid layout where the number of rows and columns changes depending
 // on the size of the container. It is designed to be used with an overflowing
 // container. If the container does not overflow in the correct direction, the
diff --git a/layouts/grid.go b/layouts/grid.go
index d09d6aa..80f7ee9 100644
--- a/layouts/grid.go
+++ b/layouts/grid.go
@@ -4,6 +4,8 @@ import "math"
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = Grid { }
+
 // Grid is a layout that arranges boxes in a grid formation with distinct rows
 // and columns. It is great for creating forms.
 type Grid struct {