Triangle Pin-down
Right angled triangles can be drawn on 4 peg, 6 peg, 8 peg etc.
Even number of pegs needed.
Equilateral triangles can be drawn on 3 pegs, 6 pegs, 9 pegs etc.
Number of pegs must be a multiple of 3.
Isosceles triangles can be drawn on any number of pegs except 3 peg
board (sometimes the isosceles are right angled too).