I decided to make up a new written alphabet. Its supposed to be hooves. I use a “” symbol for the hooves.
 
Yes, only zero to three. The numeric system we humans use has a base count of zero to nine, this is because we have ten fingers. Ponies have four hooves, so logically their numeric system would have a base of four.
 
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, would be 0, 1, 2, 3, 10, 11, 12, 13, 20, 21, 22.
 
Now with transparent background for easy copy/paste.