TO ARC :RADIUS1 :RADIUS2
SETPENWIDTH 1
MAKE "A ARCSIN :RADIUS1 / :RADIUS2
MAKE "B ARCCOS :RADIUS1 / :RADIUS2
RT :B
REPEAT 80 [RT :A / 80 FD :A * :RADIUS2 * 2 * PI / 14400 RT :A / 80]
END
