Easy binary triangle
Jelly, 7 bytes

Ṭ=Ḃµ€ŒB


Try it online!

-1 byte thanks to Erik the Outgolfer

Explanation

Ṭ=Ḃµ€ŒB  Main link
    €    For each element in (implicit range of) the input:
Ṭ        List 1s and 0s with 1s in the indices in the left argument (generates `[0, 0, ..., 1]`)
 =Ḃ      Is this equal to `(z % 2)` where `z` is the range number? (Every other row is flipped)
     ŒB  Reflect each row