Which journey rounds a grain more?
Fresh chips are angular; many sand grains are rounded. Distance can create collisions—but roughness changes the count too. Count the knocks.
Many grains begin as sharp fragments
Weathering loosens fragments. Rivers and waves can carry them, and hard collisions knock off corners over time.
Each hard knock can remove a corner
Apply up to eight practice knocks to one chip. The model makes it smaller and rounder as corners disappear.
The riverbed changes the collision count
Keep route length fixed. A rougher bed creates more hard contacts than a smooth bed in this model.
Length is only a shortcut
Compare the counted knocks, not the drawn length. Try three non-gate route pairs.
Same chips, different histories
Both chips start identical. The short rough route schedules eight hard knocks; the long smooth route schedules five. No final grain is shown.
matched starts · impacts drawn · final shapes hidden
Commit before the new setup runs.
Which route makes the rounder grain?
Run both matched chips and count every hard knock.
