A person operates a concrete power trowel in a bare room. The person, dressed in a long-sleeved black shirt and black pants, guides the trowel across a wet concrete floor. The trowel is a walk-behind machine with a black handle and a red and white engine mounted above a yellow safety cage, enclosing rotating blades. The machine smooths the concrete as it moves. The room has unfinished concrete walls and an open doorway on the right.