thickness = 5;
hole_rad = 5;
spool_rad = 150;
square_size = spool_rad + hole_rad * 4;
triangle_rad = square_size * 2 / 3;
filament_width = 10;
filament_height = 20;
filament_offset = 2;
// -1 = Left; 1 = Right
side = -1;

difference()
{
	// Base Shape
	union()
	{
		translate([square_size / 2 * side, 0, 0])
			cube([square_size, square_size, thickness], center = true);
	
		translate([0, -square_size / 6, 0])
		rotate([0, 0, -30])
			cylinder(thickness, triangle_rad, triangle_rad, $fn = 3, center = true);
	}

	// Holes
	for (i = [0:1:2])
	{
		translate([0, -square_size / 6, 0])
		rotate(-30 + i*120)
		translate([triangle_rad - hole_rad * 3, 0, 0])
			cylinder(thickness + 2, hole_rad, hole_rad, $fn = 360, center = true);
	}

	// Filament Sensor
	translate([square_size * side - side * (filament_width / 2 + filament_offset), square_size / 2 - filament_height / 2, thickness / 2])
		cube([filament_width, filament_height, thickness], center = true);
}