A carbon atom can form either a single bond, double bond or triple bond with other carbon atom. Why can't it form four bonds with a single carbon atom?

This is clear from the electronic configuration of carbon. when a carbon atom makes 3 bonds with another carbon atom there exists 1 sigma bond and 2 pi bonds,but it needs very high energy to have 1 sigma bond and 3 pi bonds thats why a carbon atom cannot make 4 bonds with another carbon atom.