The hopper pattern now runs all the way around the Iron Island chest ring. The title card calls this one "Iron Island Item Elevator Design." Basket's plan is an arc: glass rising from the ring on each side and meeting at the top, where the item elevator will come out.
Measuring the arc
First comes the math. With F3 open, Basket reads coordinates off both sides of the ring and gets 77 blocks across for the inner edge and 79 for the outer. The hope is to leave "enough gap in between the two to allow water to pour all the way from the top." The shape comes from an online circle generator, so the plan is to lay out the inner curve and stay two blocks out from it the whole way.
Height takes a couple of tries. Basket pillars up to 99 to see what 40 tall looks like, and it seems far too high. It turns out the generator's height setting covers the whole shape, so 40 there only means 20 up. Basket settles on 30 high, with the top of the arc at 88. The inside of the arc will be white glass to match the rest of the build.
Around this point JJBonsig joins the game. In-game chat shows "JJBonsig: Slept until sunrise" and "JJBonsig: Blew away the dark clouds," and then JJBonsig leaves again.
One, two, one, two
Then the counting. The generator draws the curve as a pixel grid, and Basket has to turn that into steps: "five, four, four, two, three, two, two two two two." The steps go into a notepad in small groups so Basket doesn't lose the place.
The first side goes up and stops short of where the middle should be. Basket builds the same pattern from the other side, and it ends up higher than the first. "I wonder what I've screwed up." A third copy built right next to them matches the first one, which only adds to the puzzle.
Four twos
Then a viewer points it out: "I think you forgot a 2." Basket checks the notepad. After the run of threes there should be four twos. Basket recounts it on a test build off to the side, finds the copies don't have four twos where they should, and a whole stretch of glass comes back out.
The rebuild goes slowly. Basket counts every block out loud, "one, two, two, one, two, two," down to the six ones at the very top. It meets the other side. "It's a miracle. We actually lined up with the other side."
How the water will run
With one arc done, Basket explains the rest. A second arc will cross the other way and meet this one in the center. The water item elevator will rise up the middle to the top block, and from there the water will flow in just one direction, carrying the items. Water will come down the other sides too, but it won't carry anything.
Glass, iron or sea lanterns
The stream is almost over, so there's no time for a second arc. Basket tries some styling instead. Sea lanterns go along the top, and iron blocks get a test run too. Pulling some glass out lets water run down to the lowest spot, and it breaks some redstone on the way. "Note to self, fix the redstone that used to be here." Basket goes to grab the dropped redstone before it despawns.
The favorite so far is iron on the inside of the arc for structure, sea lanterns on the outside top and sides, and clear glass where the water runs. "This will take more iron, but we're an iron farm, so that should be okay."
Before deciding, Basket wants to bring the item elevator all the way up to the top first and see how its pattern sits next to the arc. The bigger plan has paths leading up to the top and four nether portals around it, so you'd arrive inside the top section and walk down ramps. The video ends on the credits, with no gameplay after them.