Contingency codes:

(1) diagonal - go / diamond - nogo

(2) diagonal - nogo / diamond - go

Imperative codes:

(0) go

(1) nogo

Stimulus codes:

(1) diagonal - R up

(2) diamond - R up

(3) diagonal - L up

(4) diamond - L up

(l) line - both angles

(f) forty-five - R up line & diamond (45 degree angle)

(o) one-35 - L up line & diamond (135 degree angle)

(a) all - 1 & 2 & 3 & 4

Response codes:

(3) go - too late - ERROR

(4) go - on time - OK

(5) nogo - no response - OK

(6) nogo - response - ERROR

(a) all - both OK go and nogo, i.e. 4 & 5