Vizhub leson 1 TCB
This example demonstrates static SVG shapes—a brown rectangle and four nested concentric circles in red, yellow, purple, and blue—rendered inside a fixed 500×500 viewport. It also loads D3 via UNPKG and uses the `import { select } from 'd3'` statement to select a `#message` div, whose text is set to a string imported from a local ES6 module. The code highlights D3’s data binding and module integration without interactive behavior or external data sources.