checking ============== The Double Number Extension Word Set Layers

checking Nucleus layer

checks:  2!  2@  2DROP  2DUP  2OVER  2ROT  2SWAP  D+  D-  D0=  D2/
checks:  D<  D=  DABS  DMAX  DMIN  DNEGATE  DU<

checking Interpreter layer

checks:  D.  D.R

checking Compiler layer

checks:  2CONSTANT  2VARIABLE