The Sri Yantra is a diagram used as a meditation tool in some
Hindu traditions.
I don't know of any use in Buddhism.
This picture is incomplete (the lotus petals are missing).
I built it just as a first exercise in the Java programming
language.
It turned out to be a nice mathematical puzzle.
To get things right requires solving a tenth degree polynomial,
if I remember right.
I used a simple numerical technique (Newton-Raphson).
Here is the
source code
in Java, for the wildly curious.