diff --git a/fcad/cube.scad b/fcad/cube.scad
index 99ea116..ce843bd 100644
--- a/fcad/cube.scad
+++ b/fcad/cube.scad
@@ -2,15 +2,15 @@ function fCube(dims) = (
   let(x = fIsVector(dims) ? dims[0] : dims,
       y = fIsVector(dims) ? dims[1] : dims,
       z = fIsVector(dims) ? dims[2] : dims)
-  [
-    [fKeyPoints,  fCartesianProduct([[0, x], [0, y], [0, z]])],
-    [fKeyFaces, [
+  fModel(
+    points=fCartesianProduct([[0, x], [0, y], [0, z]]),
+    faces=[
       [0, 2, 3, 1], // -x
       [0, 1, 5, 4], // -y
       [0, 4, 6, 2], // -z
       [4, 5, 7, 6], // +x
       [2, 6, 7, 3], // +y
       [1, 3, 7, 5], // +z
-    ]],
-  ]
+    ]
+  )
 );
diff --git a/fcad/cylinder.scad b/fcad/cylinder.scad
index 30b1604..4efba0a 100644
--- a/fcad/cylinder.scad
+++ b/fcad/cylinder.scad
@@ -3,16 +3,15 @@ function fCylinder(h, r, r1=undef, r2=undef, sides=36) = (
       side_range = [0 : sides - 1],
       int_r1 = (r1 == undef) ? r : r1,
       int_r2 = (r2 == undef) ? r : r2)
-  [
-    [fKeyPoints,
+  fModel(
+    points=
       [for (side = side_range)
        for (params = [[int_r1, 0], [int_r2, h]])
        let (angle = side * degrees_per_side,
             radius = params[0],
             height = params[1])
         [radius * sin(angle), radius * cos(angle), height]],
-    ],
-    [fKeyFaces, concat(
+    faces=concat(
       // bottom
       [[for (side = [sides : -1 : 0]) side * 2]],
       // top
@@ -20,7 +19,6 @@ function fCylinder(h, r, r1=undef, r2=undef, sides=36) = (
       // sides
       [for (side = side_range)
         [for (vertex = [2, 3, 1, 0]) (side * 2 + vertex) % (sides * 2)]]
-    )],
-  ]
+    )
+  )
 );
-
diff --git a/fcad/sphere.scad b/fcad/sphere.scad
index d5c537c..3f14ae8 100644
--- a/fcad/sphere.scad
+++ b/fcad/sphere.scad
@@ -2,8 +2,8 @@ function fSphere(r, sides=36, stripes=18) = (
   let(degrees_per_slice = 180 / stripes,
       degrees_per_side = 360 / sides,
       top_index = (stripes - 1) * sides)
-  [
-    [fKeyPoints, concat(
+  fModel(
+    points=concat(
       [for (stripe_index = [1 : stripes - 1])
        for (side_index = [0 : sides - 1])
        let (stripe_angle = stripe_index * degrees_per_slice,
@@ -18,8 +18,8 @@ function fSphere(r, sides=36, stripes=18) = (
         [0, 0, r],  // top
         [0, 0, -r],  // bottom
       ]
-    )],
-    [fKeyFaces, concat(
+    ),
+    faces=concat(
       // side squares
       [for (stripe_index = [2 : stripes - 1])
        for (side_index = [0 : sides - 1])
@@ -49,6 +49,6 @@ function fSphere(r, sides=36, stripes=18) = (
           side_base + side_index,
         ]
       ]
-    )],
-  ]
+    )
+  )
 );
diff --git a/fcad/struct.scad b/fcad/struct.scad
index f6c1202..d13e0e1 100644
--- a/fcad/struct.scad
+++ b/fcad/struct.scad
@@ -5,6 +5,13 @@
 fKeyPoints = "points";
 fKeyFaces = "faces";
 
+function fModel(points, faces) = (
+  [
+    [fKeyPoints, points],
+    [fKeyFaces, faces],
+  ]
+);
+
 function fPoints(model) = (
   fMapLookup(fKeyPoints, model)
 );