Episode 21 of The Witness is a return trip. Basket checks old panels that never showed any error marks, gives up on most of them, and then goes back to a sandstone ruin where the puzzles are drawn by walking on the floor. Two of those fall, and the video ends with Basket heading out the exit.
Panels with no answers
It opens at a see-through blue grid in the woods. "This is one where it's a mirrored thing, and you can draw some things, but there was no indicators." Lines go in and nothing happens.
The castle near the start of the game has a gray panel full of dots, and the town has a door panel of colored dots and a panel in a wooden wall with a small yellow block shape. All of them get a try. None of them flash an error or a solve. "This one doesn't have any error messages," the commentary says, and later, "Okay, I've lost my patience."
The purple floor
Across a bridge and a field of red flowers, a sandstone ruin holds panels on posts with walkways of glass tiles around them. "Puzzles that you walk on. I've already solved some of them." The purple one gets reset and tried again by walking the tiles. A few tiles are broken and cannot be stepped on. After several tries the line goes through and the path lights pink: "Ah, okay, so that was it. I don't know why I did it wrong the first time. Progress guys, progress."
Green and blue
The green panel has two block shapes and more broken tiles. One route links up where it should not ("Yeah, because we connected there"), and the next needs a way across a gap. "Oh wait, duh. There's a board there." The commentary says "We're almost there" and moves on to the blue panel.
That one turns out to be mirrored, which changes the plan: "I didn't realize this was going to be a mirror one." The rule the commentary settles on is "We can't cross this middle path here at all." Counting steps across the tiles, it ends with "Yes!" A light by a nearby gate shows green.
Where it ends
A door turns out to be a shortcut back to where these floor puzzles began. On a pillar, a small white maze panel takes a red line. "I don't really understand these puzzles," the commentary admits, then: "So that one's happy now." Basket walks out through a tunnel into a field. "Here's the exit. We have done extra credit work." The video ends there.
