This routine can be used to work out user-defined characters. An 8 x 8 grid is displayed on the screen and a cursor can be moved round it using Q, W, U and 8. Squares can be filled by pressing Z and cleared by pressing X.

Once the character is complete, press TAB to find the decimal values of each line. They can then by typed after VDU 23,224 and the character will then be displayed by pressing VDU 224.

Definer was written for the BBC computer by Edmund Quck of Mitcham, Surrey.