Not through dialog boxes. Through the Event Viewer. A translucent window appeared behind his Properties palette—a window he hadn't opened. It was the Output tab from Visual Studio, but the debug messages were wrong.

Each triangle's elevation flickered, just for a frame, showing a different number. 174.32 became 174.33, then 174.31, then back. It was as if the surface was breathing.

He saved the drawing. The file size was 48.2 MB. He saved again. 48.9 MB. He hadn't added anything.