there are three different situations how a cylindrical peg could be placed:
1. perpendicular the ground. The shape of the top of the hole is a circle. The diameter of the hole is the same as the diameter of the peg.
2. The peg is driven in the ground under an angle between 0° and 90°. Than the shape of the hole is an ellipse.
3. The peg lies flat on the ground and is stamped into it. The shape will be a rectangle or because pegs mostly have a sharp point it is a rectangle with an additional triangle.