If you stipple something, that means you add tiny dots of color or texture, such as using a special painting tool to stipple a plain wall with dots of a different color to make it look more interesting.
The verb stipple came into English from the Dutch word stippelen, meaning "to spot or dot.” Artist stipple paint onto their canvases and from the distance, the dots look like a field of flowers. You can also stipple metal, by poking it with a tool that creates little circular dents — that look like dots — to give it an artistic look.