If you are outputting to a terminal, you may want to control the positioning of the cursor:
Put the curser at position x y. The top left-hand corner of the display is at 0 0.
With the current position at x y, put the cursor at x+dx y+dy.
In order to know where to position the cursor, it is often helpful to know the size of the screen:
And sometimes you want to use:
Clear the screen
Note that on non-terminals you should use #ff emit, not
page, to get a form feed.