ddrop:  drop drop exit
rot:    tor swap rfrom swap exit
over:   tor dup rfrom swap exit
not:    dup and exit
and:    nand dup nand exit
or:     dup nand swap dup nand nand exit
negate: dup nand lit 1 add exit
subtract: dup nand lit 1 add add exit
nondextructive-subtract: enter over enter over enter subtract exit
shl:    dup add exit       ; AKA '2*', "two-star", '<<', shift-left