Connecting Shapes
The CHAIN method in five minutes — one real question, built piece by piece.
Three or four grey pieces are shown, and some of their edges carry letters. You pick the picture of the shape the pieces make.
The letters mark joins, not pieces. Each letter sits on two edges, on two different pieces, and those are the edges that meet. Two small marks either side of a letter show exactly which stretch of edge it means.
So the pieces make a chain: a joins the first piece to the second, b joins the second to the third. Only a piece in the middle of the chain carries two different letters.
The video above and the worked example below take apart the same question. One thing is different: the video shows the five pictures in another order, so the answer is lettered E in the video and A here. Same picture, different place in the line-up.
The method
Five beats: check the letters, hold the first piece still, add the next piece, imagine the whole shape, narrow it down — and their first letters spell CHAIN.
- Step 1 of 5
Check the letters
Every letter is on two edges, on two different pieces, and those two edges join. Find both of each letter before you move anything. Three pieces means two letters; four pieces, three. The piece with two letters sits in the middle of the chain. - Step 2 of 5
Hold the first piece still
Start with the first piece and keep it exactly as it is drawn. Do not turn it. Everything else comes to it. - Step 3 of 5
Add the next piece
Find the twin of its letter, then turn the next piece on the spot until the two lettered edges meet face to face. Turning is allowed. Flipping is never. Then the next letter, and the next, until every piece is on. - Step 4 of 5
Imagine the whole shape
The joins disappear: the answer pictures are plain outlines. So picture the outline before you look at the options, and put it into words in your head — "a U with a tall post on one arm". - Step 5 of 5
Narrow it down
Check each picture against your shape and cross off any that do not match. The whole shape may be drawn turned round, and that still counts, so turn it in your head before you cross a picture off. Flipped over, it never counts. One picture is left.
About 25 to 35 seconds each. These are among the slowest on the paper.
Rules to watch
- In our questions, every join edge is straight and one square long. What varies is which way a piece must turn to bring that edge round. Some practice books join sides of different lengths: they still touch along the lettered sides, and the pictures show how they line up.
- Turning is allowed. Turning over is not. A piece keeps the same shape when it turns. Turned over, it becomes a different piece.
- Nothing overlaps and nothing is lost. The finished shape holds exactly as many squares as the pieces do together, in all twenty of our exam-level questions.
- But counting squares decides almost nothing. 64 of our 80 wrong pictures hold the right square count. Counting catches one family only.
- Hold the first piece, not the middle one. In our questions the answer always shows the first piece exactly as it is drawn, so holding it still builds the shape the right way up. Holding the middle piece still instead builds most of our exam-level answers upside down.
- The answer may be the whole shape turned round. Ours never are, but practice books often draw it that way: 8 of the 12 we worked through from one GL-style book. Turned round still counts. Flipped over never does.
- Expect three or four pieces. Easier practice sets use two, which needs no chain. Every exam-level question here uses three or four.
Watch for these traps
We looked at all 80 wrong pictures in our twenty exam-level questions. They share out evenly: five families, each used exactly 16 times. None is rarer than another, so all five are worth knowing.
- Joined on the wrong edges. The right pieces, in a sensible arrangement, meeting where no letter said. It usually looks tidier than the real answer. Beat A is the guard: follow each letter to its twin before you join anything.
- A piece turned to the wrong angle. The right edges really do meet, but one piece sits a quarter turn out, so the rest of it points the wrong way. Look at the far end of that piece: the joined end is right in every picture, so it can never tell them apart.
- Turned over instead of turned round. One piece flipped, or the whole shape drawn as a mirror. On a table, flipping a piece feels like the same sort of move as turning it. Pick one piece that has a left and a right — often the first piece — and check it is still the same way round.
- A piece you were never given. One piece swapped for a near twin — a straight bar in place of a zigzag. It holds the right number of squares, so counting is no help, and nobody re-checks the pieces once the layout looks right. Beat N catches it: find each of your pieces in the picture.
- Squashed together. One piece pushed a square into its neighbour instead of meeting it edge to edge. This is the only family counting catches, and it is easy: every one of the 16 comes out exactly one square short.
Stuck? Work down this list rather than guessing.
- Count the squares once. Cross out the picture that is one short. Then stop counting.
- Join just two pieces. Do the first letter only, and see which pictures contain that pair.
- Check each picture against the pieces on the left and hunt the one you were never given.
- Still nothing at 25 seconds? Pick from what is left and move on. Do not start again — a second go almost always repeats the first.
Try these yourself
Now have a go yourself — tap the shape that the pieces make.
Related
- The complete 11+ question-type guide
- Hidden Shapes — the same ordered tracing, on a busy figure
- Complete the Shape — find the piece that fills the gap
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.