Yes, Master

Today a brother and sister were playing with our blocks at the library, seeing how tall they could build a tower. He was maybe 4 and she was around 5. As things got wobbley and looked like they could fall at any moment, they argued over who would add the next block. She won the argument with the proclamation, "I am the master of this!" Maniacal laughter did not follow, but it wouldn't have been inappropriate.