Types: start, end, delta (positive or negative)
What this prototype does
Draws a native, fully editable waterfall chart as PowerPoint shapes on the currently visible slide — no images, no proprietary blob. Every rectangle, connector, and label is a standard PowerPoint object you can move, restyle, or delete manually.
This is the same architecture think-cell uses, built on modern Office.js instead of legacy VSTO — which is why it runs on Windows, Mac, iPad, and the browser from the same code.