--- a/src/Grids/grid.jl	Sat May 25 16:07:10 2024 -0700
+++ b/src/Grids/grid.jl	Sun May 26 17:35:52 2024 -0700
@@ -128,6 +128,16 @@
 function boundary_indices end
 
 """
+    orthogonal_grid(g::Grid, id::BoundaryIdentifier)
+
+The grid for the coordinate direction orthogonal to that of the boundary
+with given id
+"""
+function orthogonal_grid end
+
+function boundary_indices end
+
+"""
     eval_on(g::Grid, f)
 
 Lazy evaluation of `f` on the grid. `f` can either be on the form `f(x,y,...)`