Models and the long read
Interactive
Two standalone pages, best opened full screen. Both are built on the exact LTB solution from the pbhgr library; the numbers are checked against the Python version.
A PBH seen from a particle
A three.js model: the collapse of an overdensity seen by one dust grain (at the centre, at the edge, far away), horizon growth MAH(τ), reverse play and time speed-up. A second mode, "inflaton fragment", draws a random curvature field in which the high peaks become PBHs before reheating.