I designed this mold in 123D Design for the Math based challenge. I followed a basic pentagon with 5 pentagons inside pattern, reducing the height by a factor of 3 for each level. This fractal design uses it's inherent simplicity and aesthetically pleasing form to make the perfect sandcastle mold, plus it's a turtle! Make your next beach visit a ball, well a pentagon in this case, with Penta Mathmaturtle Palace.