【Question 10】The Soma cube is a set of 7 small cubical blocks invented by the Danish physicist Piet Hein (as shown in the figure). If we assume that the edge length of these small cubes is 1, then using these 7 blocks, one can not only form a $3 \times 3$ cube but also many other beautiful geometric shapes. To form the geometric shape below, the 3 Soma cubes needed are $\qquad$.

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First, determine how many unit cubes (small cubes with an edge length of 1) the target shape requires. As shown in the left figure, a total of 11 are needed. The Soma cube No. 1 contains 3 unit cubes, and Nos. 2 to 7 all contain 4 unit cubes. The target shape requires 3 Soma cubes, which can only be $11=3+4+4$, so No. 1 must be chosen. Then, through observation, it is found that No. 1, No. 3, and No. 5 or No. 1, No. 3, and No. 6 are valid. (No. 3 is placed at the bottom and kept in the position shown in the figure, and No. 1 is placed on top of No. 3.)