Ernie at his window box.
The window box for the first set of CG segments in Episode 4125.
Ernie's window box, located outside the window of Ernie and Bert's apartment, is a small garden which also serves as the home of the Twiddlebugs.
The Twiddlebug family resided in a milk carton house decorated with miniature furnishings, such as a postage stamp of George Washington. In the more recent computer-generated appearances, the house has been updated to a Chinese food carton; however the inside remains the same (complete with the upside-down Washington stamp on the wall).
Other Twiddlebug homes and communities exist in other window boxes on Sesame Street, such as a Twiddlebug Town, which is located in Elmo's window box.