bytecode:
    [start,1,2,3,4][map,[plus,3][gt,2]][is,[_]]

type inference
    [obj{0}, int{4}, [[int, int, bool]], bool{4}, [[bool, bool]], bool{0,4}]

obj{0} - [start] is initial
int{4} - [start] emits 4 ints
bool{4} - [map] processes an int at a time and produces a bool (4 times)
bool{0,4} - [is] filters on true/false and thus, 0 to 4 bools will pass.