Drawing is done on a 2D grid similar to conventional drawing tools, BrushTone starts with a one pixel sized brush in the lower left corner of the screen. You can move the brush with the keyboard arrow keys, which is the preferred method, or the mouse, then press either the space bar or the left mouse button to paint the currently selected color to the canvas, move the cursor to another adjacent pixel and change it, etc. Note that the mouse doesn't work with any other tool except the pencil tool. You can also pan the view window around using the W,A,S,D keys in order to draw across other parts of the canvas. The Z key can tell you the current color under the cursor so you can check if the color changes, and you can press the C key to tell the exact position of the cursor on the canvas.