A varve is one year of still-water sediment: a pale band laid down by the summer melt, a thin dark band by the quiet of winter. Stack them and a lake bottom becomes a calendar you can count.
Click to deposit a year. Move the mouse up and down to set the climate — warmer summers lay thicker pale bands. Count the couplets to read the elapsed time.
click: deposit a year · move: climate · drag: deposit fast