diff --git a/bitmap/name_tag.scad b/bitmap/name_tag.scad
index 7687c54..366dce0 100644
--- a/bitmap/name_tag.scad
+++ b/bitmap/name_tag.scad
@@ -7,33 +7,30 @@ http://creativecommons.org/licenses/by/3.0/
 
 use <bitmap.scad>
 
-// change chars array and char_count
-// OpenSCAD has no string or length methods :(
-chars = ["R", "E", "P", "R", "A", "P"];
-char_count = 6;
-
-
-// block size 1 will result in 8mm per letter
-block_size = 2;
-// height is the Z height of each letter
-height = 3;
-// Append a hole fo a keyring, necklace etc. ?
-key_ring_hole = true;
-
-union() {
-	translate(v = [0,-block_size*8*char_count/2+block_size*8/2,3]) {
-		8bit_str(chars, char_count, block_size, height);
-	}
-	translate(v = [0,0,3/2]) {
-		color([0,0,1,1]) {
-			cube(size = [block_size * 8, block_size * 8 * char_count, 3], center = true);
-		}
-	}
-	if (key_ring_hole == true){
-		translate([0, block_size * 8 * (char_count+1)/2, 3/2])	
-		difference(){
-			cube(size = [block_size * 8, block_size * 8 , 3], center = true);
-			cube(size = [block_size * 4, block_size * 4 , 5], center = true);
-		}
-	}
+/*
+ chars = chars array
+ char_count = number of characters (OpenSCAD has no string or length methods)
+ block_size = letter size (block size 1 will result in 8mm per letter)
+ height = the Z height of each letter in mm
+ key_ring_hole = (boolean) Append a hole to a keyring, necklace etc. ?
+*/
+module name_tag(chars = ["R", "E", "P", "R", "A", "P"], char_count = 6,
+    block_size = 2, height = 3, key_ring_hole = true) {
+  union() {
+    translate(v = [0,-block_size*8*char_count/2+block_size*8/2,3]) {
+      8bit_str(chars, char_count, block_size, height);
+    }
+    translate(v = [0,0,3/2]) {
+      color([0,0,1,1]) {
+        cube(size = [block_size * 8, block_size * 8 * char_count, 3], center = true);
+      }
+    }
+    if (key_ring_hole == true){
+      translate([0, block_size * 8 * (char_count+1)/2, 3/2])	
+      difference(){
+        cube(size = [block_size * 8, block_size * 8 , 3], center = true);
+        cube(size = [block_size * 4, block_size * 4 , 5], center = true);
+      }
+    }
+  }
 }
diff --git a/bitmap/test_name_tag.scad b/bitmap/test_name_tag.scad
new file mode 100644
index 0000000..a921491
--- /dev/null
+++ b/bitmap/test_name_tag.scad
@@ -0,0 +1,19 @@
+include <../bitmap/name_tag.scad>;
+
+translate([0,0,0])
+name_tag(["n","a","m","e","_","t","a","g"], 8);
+
+translate([20,0,0]) // 0 + 16/2 + 16/2 + 4
+name_tag(["N","A","M","E","_","T","A","G"], 8);
+
+translate([52,0,0]) // 20 + 16/2 + 40/2 + 4
+name_tag(chars=["n","a","m","e","_","t","a","g"], char_count=8, block_size=5);
+
+translate([96,0,0]) // 52 + 40/2 + 40/2 + 4
+name_tag(chars=["N","A","M","E","_","T","A","G"], char_count=8, block_size=5);
+
+translate([130,0,0]) // 92 + 40/2 + 16/2 + 4
+name_tag(["n","a","m","e","_","t","a","g"], char_count=8, height=30);
+
+translate([150,0,0]) // 130 + 16/2 + 16/2 + 4
+name_tag(["N","A","M","E","_","T","A","G"], char_count=8, height=30);