Download Rainbow 3D Blocks chrome extension. A nice rainbow block theme that should look very fancy on your computer screen. Note that it works best on Chromebooks. and install in your Google chrome browser. This is Direct Rainbow 3D Blocks Crx download for Chrome it is also called Rainbow 3D Blocks offline CRX for chrome Download. This Rainbow 3D Blocks is used to A nice rainbow block theme that should look very fancy on your computer screen. Note that it works best on Chromebooks.