Origami magic ball pattern

I can't find a good non-video set of instructions for this pattern, so here's an attempt. It's also nice to put things I've learned into writing, although I think this document is full of unnecessary details that the reader would figure out on their own had they followed the pattern a few times. These details might help make the first attempt less of a disaster, but they could also be intimidating and exhausting. Is the reader playing or are they obeying? I sure hope this isn't analogous to anything being taught to me…

Info

Instructions

Paper

Dimensions: flexible (literally). If you want to make a ball, half of a letter-sized piece of paper lengthwise (hot dog) will do. A 2:1 rectangle is also a good shape.

Size: Difficulty scales with the number of square cells more than the size of the cells, so using a post-it note won't make this impossible like other origami projects you might have tried.

Type: I don't recommend thin origami paper. Printer paper is fine.

Methods

There is an easier method and a harder method. The easy way adds some folds unnecessary to the final product, but allows you to complete the "collapse" step column by column. The hard way has the collapse of each cell depend on the collapse of its neighbours, so the whole sheet has to be massaged for a couple hours before it all collapses at once. Take your pick!

Steps (easy, procedural)

  1. Cell pre-folding: Horizontal axis (rows)

    Make mountain folds across the sheet lengthwise (even thinner hot dog), dividing it into as many equal rows as you have time for. This will define your cell size. 8 rows is a solid number on half-letter-sized paper.

    Note that, in general, there's less accumulation of error when you fold a sheet in half, then quarters, then eighths… compared to doing it japanese-fan-as-a-child style.

  2. Vertical axis (columns)

    Use mountain folds perpendicular to the folds made in step 1 to fill the sheet with columns of squares. Then, double the amount of columns by mountain-folding each column in half. It's okay if there's a partial column at the end.

    In this sheet full of 2:1 rectangles, the "cells" are any set of squares arranged in a brick-like pattern, so each cell takes up two of these rectangles, and is neighbours with 6 other cells. This becomes important in step 4.

    Cells drawn onto a sheet
  3. Making collapse easier

    Fold each of the rows created in step 1 in half. These folds will go through the middle of each row of cells.

    Also make sure all of these new folds and the ones in step 1 are creased both ways: mountain and valley.

  4. Diagonal pre-folding

    Figure out where your square cells will be. For each cell, place an X in it with two valley folds extending to all four corners.

    This may take a while. It is also incredibly easy to mess these up.

    All prepared for step 5 (paper is upside-down)
  5. Collapse

    It's probably best to look at the pictures for this one but I'll do the screenreader challenge.

    Collapse happens half a column at a time—your goal is to have each cell fold inward (concave/valley to you, so maybe outward) so that its border makes a bowtie shape (or hourglass with the paper held in portrait orientation). The paper won't lay flat (ever again), but unlike with the hard method, you'll have a "done" section that's flattenable like an accordion is. Every half-column, the lengthwise folds reverse orientation.

    Start of collapse
    Several columns collapsed

Steps for the incredibly patient

Skip steps 3 and 5 above. Most of the pre-folding is the same.

To replace step 5, you also want to start at one end due to technical limitations of human hands, but you won't be able to collapse any column without the collapse of adjacent columns. You'll just have to coax the entire sheet bit by bit. It's kind of relaxing, although I don't know how relaxing something really is when an internet person is telling you to be relaxed about it.

Making a ball (optional)

You'll have to undo both ends temporarily. It just takes a bit of tape and a lot of convincing the tape to behave like paper. Unfortunately, once you tape both ends together, you lose the ability to fold the ball fully (think of an accordion with its ends glued together). Origami paper is especially bad for this since it's much less opinionated than tape on what shape to hold. Smaller square cells are also more easily overpowered by tape than large ones.

Done!