Mister Rogers' Neighborhood (1968)

Season 8: Episode 7

Mister Rogers arrives with some large building blocks which he uses to build a tower, a street, and a car. He thinks about some young friends who used blocks and crates to make a pretend fire engine. In the Neighborhood of Make-Believe, Mr. McFeely delivers some building blocks to the Platypus mound and Daniel is concerned that the blocks might be used to build "something bad." When Lady Aberlin builds with the blocks, they start to dance around on their own. She and X the Owl (who is pretending to be a fireman) are amazed until they realize that Lady Elaine Fairchilde has attached strings to the blocks.