profile p1 x 3 y 1 x -2 y 2 x -1 y -3 prism pr1 p1 0 0 1 profile p2 x 0.5 y 0.5 x -0.5 y -0.5 trotate p2 0 0 0 1 0 0 90 ttranslate p2 1 4 0.25 trotate p2 0 0 0 0 0 1 -15 explode pr1 f compound pr1_3 pr1_4 fu featprism pr1 p2 p2 -2 -4 0 1 1 featperform prism result fu set square 26.9296