You are given a list of (x, y) co-ordinates. Any three of these could be the vertices of an isosceles triangle. Create a function that determines how many isosceles triangles can be drawn from this scattering of points. Vertices can be shared by multiple triangles.
find_triangles([(0, 0), (0, 4), (2, 2)]) ➞ 1
find_triangles([(-10, -10), (-7, 3), (-3, 3), (-2, 7), (9, -7)]) ➞ 0
find_triangles([(7, -5), (-7, -4), (1, 8), (-7, 5), (1, -3), (3, 1), (-1, 2), (3, -1), (-1, 1), (6, 4)])) ➞ 3
# The 3 isosceles triangles for the last example are:
# ((1, 8), (3, 1), (-1, 1))
# ((1, -3), (3, 1), (-1, 1))
# ((1, -3), (3, -1), (-1, 1))
An isosceles triangle has two sides of equal length.