1. Prepare the puzzle: Make sure you have a complete puzzle, including seven small pieces with different shapes.

2. Observe the shape of the crab: first observe the shape of the crab and pay attention to its head, body, claws and legs.

3. Analyze the shape of crab: Divide the shape of crab into several basic geometric shapes, such as square, rectangle and triangle.

4. Disassembling the puzzle: Disassemble the seven small pieces of the puzzle, and then try to find out the small pieces similar to each part of the crab according to the shape of the crab.

5. Splicing of crab shape: Use the removed small pieces to gradually splice according to the shape of the crab. You can refer to the pictures or models of crabs to ensure that the position and angle of each piece are correct.

6. Adjustment and optimization: In the process of splicing, some small pieces may not fit perfectly. You can try to adjust and optimize the position and angle of the small pieces until they are finally spliced into crabs.

7. Check and correct: After the splicing is completed, carefully check whether the shape of the crab is accurate. If there is something wrong, you can correct it until you are satisfied. Please note that puzzles require a certain degree of spatial imagination and hand-eye coordination. If you are a beginner, you may need some practice to piece together a crab successfully.

Matters needing attention in using jigsaw puzzles

Direction and angle of small pieces: each small piece has a fixed direction and angle and must be placed in the right position. Wrong direction or angle may lead to splicing failure or incorrect shape. Spatial imagination: Tangram is a three-dimensional puzzle, which needs a certain spatial imagination to predict the position and shape of small pieces. Practicing spatial imagination can help you better put together puzzles.