Worked Walkthroughs

Three real items from the practice generator, solved end to end. Nothing new here — the same three eliminations in the same order every time, plus the one rule that stops you throwing away the answer.

The order, once

Read the object and work out its outlines. Then, against the five openings: rings out, size out, walk the features. Rings cost nothing because they need no comparison at all. Size costs almost nothing because the five openings are drawn at one shared scale, so you can compare them against each other by eye. Only what survives both is worth a feature-by-feature walk. And at no point does orientation eliminate anything.

Item 1 — size does the work

Item 1, as it arrives.

Nothing here has a ring in it, so the first check comes up empty and costs you a glance. Go to size.

C is the same outline as A, at about three-quarters the size. Lay them side by side: identical proportions, identical shape, one visibly smaller. Because the five openings share a scale with each other, a shrunken copy of a true outline is a shrunken copy — it cannot admit what the full-size one admits. C is out. Note that C is also drawn flipped, its point on the other side, and that is not why it is wrong; it would be just as wrong facing the same way.

Now walk what is left. A carries a triangular point jutting off one long side of an otherwise straight bar. B has a squared-off tab there instead of a point. D tapers to a point across its entire width rather than off one side. E has a step and no point at all. Only A carries the feature in the place and shape the object puts it.

A ✓

The correct opening is the object's front outline.

Item 1 solved. C is A's outline at about three-quarters the size; B, D and E each shape that side of the bar differently.

Item 2 — when proportions cannot help you

Step through this one. Each step is the same item at a different stage of the solve.

Solving a medium item, step by step Step 1 of 4

1. Read the item

Object on the left, five openings. Do not start matching yet.

Item 2, untouched.

2. Work out the object's outlines

Take the object alone and build its three shadows in your head. From medium difficulty up, the answer favors the busiest of them — the one with the most corners — about two times in three, so start there and confirm rather than assume.

The object on its own. Build its three shadows before looking at the openings again.

3. Rings out, size out

Two openings go without any comparison to the object at all. C has a closed ring inside it — impossible for a hole cut in a plate, so it is wrong whatever the object looks like. B is another opening's outline at about 72%: same shape, visibly smaller than its siblings at the shared scale. Three left.

The five openings at their shared scale. Two of them go without any reference to the object.

4. Walk the features

Here is the lesson. D and E are the same overall size and the same overall proportions — measure them all you like and you will not separate them. Walk the steps instead: E is a wide band with one narrower band along a single edge, one step. D has the wide band in the middle, with a narrow band at each end, two steps. E is the answer, and only counting found it.

ring inside — impossible

E ✓

The correct opening is the object's end outline.

Item 2 solved. D matches E in size and proportions and differs only in how many steps it carries.

All four steps are printed below one another if this stepper does not respond.

That pair is why the near-miss openings are hard. They are not the answer bent out of shape — each one is the true shadow of a slightly different object, a real solid with a feature moved or dropped or resized. A shape that could genuinely exist is a shape that looks right.

Item 3 — a hard item, same three checks

Item 3, a hard item: a much busier outline, and the same three checks.

The outline is much busier: two uprights joined by a band across the middle, with steps and a shoulder on one of them. Nothing about the method changes.

Rings out. E carries a closed ring — gone, in the time it takes to look.

Size out. A is the answer's outline at about three-quarters, identical proportions and all. Gone.

Walk the last two. D runs about 2.1 to 1 where the answer is about 1.25 to 1 — far too elongated, and proportions alone settle it. B is much closer in proportion and needs the walk: its lower half tapers away to a point, where the answer's two uprights both run the full height. C is left, and the engine's own note confirms it is the object's front outline.

C ✓

ring inside — impossible

The correct opening is the object's front outline.

Item 3 solved.

Three items, three difficulties, one procedure. The hard item did not ask for a technique the easy one lacked — it asked for the same three checks against more outline.

Explain it to yourself out loud

After every practice item — the ones you got right too — say the solve in one breath: what the ring check killed, what the size check killed, and which feature separated the last two. Where you stall is the step you have not automated yet.

Do this in review because the practice page will not do it for you. It names the view the correct opening came from, which is worth having; it does not tell you why the four wrong ones were wrong. That part is yours, and it is the part that transfers.

Then go get more items. The keyholes practice generator will hand you as many as you want, at all three difficulties.

The takeaway

Rings out, size out, walk the features — in that order, because the first two are nearly free and the third is not. Openings are drawn at one shared scale with each other, so a shrunken copy really is smaller; the object's own drawing is on its own scale, so never measure an opening against it. When two survivors share size and proportions, only a feature-by-feature walk decides, and orientation never eliminates anything.

Worked Walkthroughs

Summary

Practice Questions

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