左

Bottom 工 - also 左's indexing radical. Pictures a carpenter's square or builder's tool. Added later to disambiguate 左 from 右: 左 (hand + tool) became 'the assisting hand at work' while 右 (hand + 口 mouth) became 'the speaking hand'. This minimal pair is the easiest way to remember which is which.

Top two strokes - a stylized hand graphic. Oracle-bone 左 was a left hand mirroring the right-hand 又, both drawn with the same minimal hand shape; the printed Kaishu form here is graphically equivalent to 又. Functions as the laterality marker, paired below with 工 to distinguish 左 from its mirror 右 (hand + 口).