I'd like to know what function this converges to:<p>rect(x) • rect(x/2) • rect(x/4) • ...<p>Where • is the convolution operator.<p>Unlike the series in the video, 1 + 1/2 + 1/4 + ... converges. So this function has compact support, and the value at 0 does not dip.<p>I expect it to be a <a href="https://en.m.wikipedia.org/wiki/Bump_function" rel="nofollow">https://en.m.wikipedia.org/wiki/Bump_function</a>