Make sure the post is 'square' to the floor. [=make sure that there is a right angle where the post and the floor meet]
I'll go on the trip if I can 'square it with' my parents. [=if my parents will agree to let me go]
Here's the rest of the money. Now we're 'square'. [=now we don't owe each other anything]
(..) You... Kung fu is dead? Fine! You stay in your prison of fear with bars made of hopelessness. And all you get are three square meals a day of shame! With despair for dessert. We'll take on Shen and prove to all those who are hungry for justice and honour that kung fu still lives! (..)2011 Kung Fu Panda 2