1? DIMENSION
2 (
3+ ,
3 %bound
4 )

bound:

1? 
1 %lower-bound
1.1 -:
1 *:
2 %upper-bound
2 *

lower-bound:

1! 1
1?
1 expression
1.1? REFER(variable)

upper-bound:

1 expression
2? REFER(variable)