Fig. 1.

(A) Snapshot (to scale) of the model gel with some examples of knotted configurations. Note that, to model a physical gel, a simple cubic structure is randomly cut to create dangling ends. (B) Equilibrium configurations of some of the knots considered; it can be readily seen that the size tends to be smaller as the knot becomes more complex. The knots pictured in A and B are trefoil ($3_1$), red; figure of eight ($4_1$), orange; pentafoil ($5_1$), yellow; Stevedore’s ($6_1$), green; and nonafoil ($9_1$), gray.