`PMX demonstration. Requires PMX 15.44B or later.

enter pmx /direct

macro ring
 .cyl (n,1) 1, "column"
 .cyl0 "base", 0,  v1, 2*r+d
 .cyl0 "deck" , v2, v2+v1, 2*(r+d)
 .cyl0 "tower" , v2+v1, v2*2, r*2/3
 .render
/

macro cyl
 l:=r*COS(a)
 t:=r*SIN(a)
 a:=a+da
 .cyl1 "%2",%1, l, t, v1, v2, d
/
macro cyl0
 .cyl1 "%1" , , 0, 0, %2, %3, %4
/
macro cyl1 
 create %1%2.s
  class hull
  inb -99
  cyl (24) %3, %4, %5, %3, %4, %6, %7
 //
/
macro render
 macro surf
  surface (%%91*) %%91; color:%%92; opacity:1
 //
 .surf "column", "orange"
 .surf "base", "blue"
 .surf "deck", "drab"
 .surf "tower", "violet"
 render column, base, deck, tower; cam:20, 20; jpeg:ring.jpg 
/

real l, t
real r:=30., d:=10., v1:=4., v2:=50., a:=0.
card n:=6
real pi:=3.14159
real  da:=2.*pi/n

.ring

quit pm