Stretcher bar

So, a stretcher bar is like a big Lego piece that you use to make a canvas painting. It is made of wood and comes in four pieces - two long ones and two short ones. You fit them together like a puzzle to make a rectangle or square shape, depending on how big you want your painting to be.

Then, you take the canvas, which is like a big piece of cloth, and stretch it tightly over the stretcher bar frame, like you would stretch a rubber band over your fingers. You use special tacks or staples to hold the canvas in place on the back of the frame.

Now, the canvas is all stretched out and ready for you to paint on it. When you are done painting, you can take the stretcher bar frame apart and take the canvas off, or you can leave it on there to display your painting.

So, the stretcher bar is like a tool that helps you make a canvas painting by holding the canvas tight and flat while you paint on it.