四季成因图白板动画

Hand-drawn diagram of why we have seasons: a bright yellow sun in the centre and a thin dotted oval orbit around it with no arrows. The Earth is drawn four times on the orbit, at the far left, the far right, the top and the bottom. Each Earth is a blue and green globe with a thin dark axis line through its north and south poles, and the axis is tilted the same amount and leans in exactly the same direction (top of the axis leaning to the right) on all four Earths, parallel to each other. Beside each Earth stands one small tree: next to the left Earth (north pole leaning towards the sun) a tree full of green summer leaves; next to the right Earth (north pole leaning away from the sun) a bare winter tree with a little snow; next to the top Earth a tree with pink spring blossoms; next to the bottom Earth a tree with orange autumn leaves. Nothing else in the picture. Coloured pencil and watercolour marker, clean black ink outlines, warm off-white paper, no text.