=; names the value built below it, then runs the block above with that name in scope.

=;(n=@ (mul n n) 5) is 25.

%: calls a gate with several arguments, gathering them into one sample.

%:(add 2 3) is 5.

irregular forms:

(gate a b c) is %:(gate a b c)

mul multiplies two atoms.

(mul 3 4) is 12.