Complete the Shape
The PATCH method in four minutes — one real question, the piece tipped over and dropped into the gap.
You are shown a finished shape, and the same shape with a piece missing. Then five loose pieces. You pick the one that fills the gap exactly.
A piece may be turned any way round, even tipped over onto another face. The big shape stays as it is.
These come from practice books, not from GL's own booklets, and the practice books we checked let pieces turn too.
The video above and the worked example below take apart the same question. One thing is different: the video shows the five pieces in another order, so the answer is lettered D in the video and A here. Same piece, different place in the line-up.
The method
Five steps: picture the gap, add up its cubes, too many or too few, can it turn to fit, how does it bend — and their first letters spell PATCH: the piece you want patches the gap.
- Step 1 of 5
Picture the gap
Compare the two shapes. Whatever the finished shape has, and the other one hasn't, is the missing piece. Picture it on its own before you look at a single piece. - Step 2 of 5
Add up its cubes
Count the cubes in the gap, not in the two piles. A pile can hide cubes behind other cubes. The gap you have pictured hides nothing. - Step 3 of 5
Too many or too few?
Cross off every piece that hasn't got the same number of cubes as the gap. - Step 4 of 5
Can it turn to fit?
Turning is allowed, even tipping over. Picture each piece that is left turning until it lies just like the gap. - Step 5 of 5
How does it bend?
Line the piece up with the gap, then check where its last cube goes. If it bends the other way, it is the mirror image, and no turn can fix that. Keep the one that bends like the gap.
Give each question 30 to 35 seconds.
Rules to watch
- Only the piece turns. Never turn the big shape to help a piece fit.
- A piece drawn at another turn is not wrong. Pieces may be turned any way round, so a piece that matches once it is turned is the answer. Other question types forbid turning. Don't carry that rule across.
- In our questions the gap is three, four or five cubes. A count of one, two, or six or more means you have missed part of it. Go back and look again.
- A gap of three cubes has no mirror image. Any shape of three cubes or fewer is its own mirror image, so there is no mirror to catch.
Watch for these traps
- Off by one cube. Lots of wrong pieces are just the gap with one cube added or taken away. It looks almost right, so count before you look. In the example, D is the gap without its end cube. In our bank, 55 of the 80 wrong pieces are one cube out, and 9 more are the gap at double size. The count catches those too.
- The mirror image. It has the same number of cubes as the gap, so counting never catches it. Only the bend does. In the example, that's E. In our bank it is on 16 of the 20 questions, and it is the only wrong piece with the gap's own count.
- Hidden cubes. A pile can hide cubes behind other cubes, so a pile counted by eye comes out short. In the example, the finished shape hides two cubes you can't see. Count the gap instead. In our bank, counting both piles by eye and taking one from the other gives the wrong number on 15 of the 20.
Stuck at 35 seconds? Count the gap and cross off on the count. On most questions that leaves just two pieces. Then choose on the bend, even if you are unsure.
Try these yourself
Now have a go yourself — tap the piece that completes the shape.
Related
- The complete 11+ question-type guide
- Building Blocks — which set of blocks builds the shape
- 3D Rotation — the same check on which way it bends, on the whole shape
All example questions come from the Brainblox question bank — practise this question type inside 25+ learning games, timed mock exams and focused practice. Brainblox is an independent app: not affiliated with, endorsed by or licensed by any exam board, school or assessment publisher, and it contains no past papers.