In this short #BASIC program from #microhobby you must move the black pieces to the place where the red ones are, and vice versa. The black pieces move from left to right, and the red pieces move the opposite. No piece can move backward, and you can't move a piece where another piece is.
Download it here:
https://spectrumcomputing.co.uk/entry/13634/ZX-Spectrum/MicroHobby_Semanal_077-080