Episode 27 of The Witness is about trees. It opens on white panels with branch shadows falling across them, moves into a grove of orange trees where one panel takes most of fifteen minutes, and fires a laser from there. The last ten minutes go to a single green panel full of shapes, and it is solved before the video ends.
Following the shadows
The video starts out by a run of white panels with blue grids, each one crossed by the shadow of a tree. A cable on the ground leads from one to the next. "So here's one where actually we have to look at the shadows," the commentary says, and compares it with an earlier set: "We had to avoid the shadows. This one is where we had to do the shadows."
One panel is harder than the rest. The goal is to "very roughly follow the branch," but the branch in the shadow has a break in it. Basket walks around and looks up at the bare tree against the sun. "They aren't really technically connected," the commentary says after the line goes through, "but somehow that was the answer." Then: "Where'd the gate go? What opened up?"
A panel to come back to
Down the path, Basket comes to a wooden structure that the commentary remembers trying to reach by boat earlier, and a blue panel on an orange wall. "This is a new type of thing that I haven't seen before," the commentary says, and adds, "it's possible that you're not supposed to do this part yet." It is left alone, and a look back along the cable from the last panel finds the gate that opened: "Okay, this is the gate that opened up."
Leaves and branches
The open gate leads into woods of orange trees, past tall iron gates with leaf patterns, to a yellow grid set in a stone block. The leaves and branches overhead throw their shadows across it. The first try, avoiding the shadows, is wrong. The commentary asks chat for "no hints," then later for vague ones, and a viewer suggested going around the leaves. Avoiding the leaves alone does not work either, and staying on the branches does not reach the exit.
The answer turns out to be both: "Let's avoid the leaves for that half the puzzle, and then let's stay on the branches." The line lights up. "It was a mix between the two puzzles."
Another laser
A yellow box nearby raises a laser on an arm and fires a beam across the island. "It's going to burn up those trees," the commentary says, and calls it a way of marking progress: "We have to keep on doing more of those."
The shape panel
Next is "this river area." Basket heads down to the shore, through a wooden building stacked with logs, and down stairs into a dark room. There a green grid sits beside a brown grid of dots. The green one holds a tilted shape and a vertical bar of three squares, and the commentary lays out the job: enclose an area that holds those shapes, "they can't overlap each other," and the tilted one "can actually be in any orientation." Broken spots in the grid cut off a lot of routes.
This takes about ten minutes of drawing, erasing and talking through each layout. "Sometimes it might just take half an hour." Then the line lights yellow: "Yes! See, it only took like forever."
Where it ends
With the panel solved, the commentary answers a viewer's question about how the three-tall piece works, walking through why the border had to go where it did. The video ends on the lit panel, before anything it opens is shown.