With the metaphor of a spaghetti bowl, the force you needto apply when tossing with your spoon depends on spaghetti(or filament) density, howmuch they are cooked (theirflexibility), and how they sticktogether. In particular, cells orcell assemblies are elastic, es-pecially at short time scales:when deformed, they recovertheir initial shape. Pinch yourcheek for a few seconds, it willgo back. However, at longertime scales, over minutes,days, years, cells can flow:they are viscous. Look at yourelbow skin and compare itwith a baby one : it has flown.
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