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L-triominoes

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2
Look at the picture below showing different odd sizes of triomino.
Odd triomino growing
 
Can you see a way to build round the red triomino to make the orange one?
To build round the orange one to make the grey one?
Can you continue to make a size $7$ triomino? And then a size $9$?