Lego House

Dave applied for a job at a construction company.
Once that was in the bag he loaded up his brand new van with Lego.
Drove to the building site.
He'd spend the time at work knocking up all sorts of rubbish.
When anyone complained he'd just hold up the bricks and sort of shrug.
The other builders couldn't work out what to make of that.
Eventually they joined in.
Eventually no one had any homes to live in.