box -2, -2, 18, 8
A B C triangle 13, 5, 12
c1 = circle(A, B, C)
D = center(c1)
c2 = incircle(A, B, C)
E = center(c2)
F = intersection(line(A.C), perpendicular(line(A.C), D))
G = point(c1, arg(line(D.F)):)
H = midpoint(F.G)
c3 = circle(H, radius(incircle(A, B, C)))
draw
  (A.B.C)
  c1 0: 180:
  c2
  c3
end