sub_posn

sub_posn (5,7) (1,2) == (4,5)


Dot Product

Multiply the corresponding parts and add.

dot_product (1,3) (4,7) == 1*4 + 3*7


First of

first_of [5,1,2,3] ==

"The first element of [5,1,2,3] is 5."


Pattern

Write a function creating this pattern.

n 0 1 2 3 4 5 6
value “a” “b” “c” “ab” “bc” “cab” “abbc”

What?

whaa (a,b,c) wow@[x:y:z:ws] =

a : z : wow

whaa (5,2,1) [2,4..10] == ?