|Picture||Theme||Earliest known apearance||Description|
|Open and Closed||Episode 3656||Professor Television tries to demonstrate open and closed, but his efforts backfire when the door does the opposite of what the sign says. So, he just puts up a sign saying "Nevermind".|
|Near and Far||Episode 3683||Professor Television tries to demonstrate near and far, with help from Maria's voice.|
|Danger||Episode 3713|| Professor Television tries to demonstrate "Danger" by putting a "Danger" sign above a deep drop. The sign falls, however, so he gets a large flashing "Danger" sign, which traps him.|
There are two variations of this skit, one featuring the announcer at the beginning and kid's voices saying "Danger", while another version has all dialouge muted.