1) swap number 3 and 4 at the bottom right side of the triangle
2) swap number 2 and 4 at the top right side of the triangle
3) swap number 2 and 4 at the middle right side of the triangle (number 8 should be green now)
4) swap number 4 and 2 at the middle left side of the triangle (number 12 should be green now)
5) swap number 5 and 4 at the bottom left side of the triangle (number 9 should be green now)
6) swap number 5 and 1 at the bottom middle of the triangle (number 7, 10, 11 and 13 should be green now)
7) Finally, swap number 4 and 2 at the bottom left side of the triangle (number 10 and 13 should be green now)