Quadraflop, PDP8, 4 stable states
<UL>
<LI><b>R284A</b> is a drawing of DEC's R284A.</LI>
<LI><b>R284B</b> is a drawing of DEC's R284B.</LI>
<LI><b>R2840X</b> is a 'modernized' R284.</LI>