--- /dev/null
+// -*- C -*-
+
+main_height = 95;
+
+spike_top_width = 21.04;
+
+spike_botpos_height = 9.5;
+spike_botpos_width = 11.68;
+
+topwall_width = 1.5;
+
+module NegativePlan(){
+ x4z =
+ (spike_top_width - spike_botpos_width) /
+ (main_height - spike_botpos_height);
+
+ x0 = (spike_botpos_width - x4z * spike_botpos_height)/2;
+ x1 = spike_top_width/2;
+ z1 = main_height;
+
+ polygon([[ x0, -5],
+ [ x0, 0],
+ [ x1, z1],
+ [-x1, z1],
+ [-x0, 0],
+ [-x0, -5]]);
+}
+
+module PositivePlan(){
+ w = spike_top_width + topwall_width*2;
+ translate([ -w/2, 0 ])
+ square([ w, main_height ]);
+}
+
+PositivePlan();
+//NegativePlan();