Based on the context of carving canoe paddles, your dad likely creates Geometric shapes and Organic shapes. Canoe paddles typically involve both straight, precise lines (which would fall under geometric shapes) as well as more fluid, curved lines (which are more organic).
If the question is asking for one specific answer and you're only allowed to choose one, Geometric shapes might be the most fitting, given that the paddles require precise measurements and lines. However, if it's acknowledging both aspects, then both geometric and organic shapes are relevant to his craft.