Three small squares, S1, S2, and S3, each with side 0.05 and centered at the point (4, 8, 8), lie parallel to the xy-, yz- and xz-planes, respectively. The squares are oriented counterclockwise when viewed from the positive z-, x-, and y-axes, respectively. A vector field G has circulation around S1 of 0.5, around S2 of 0.0025, and around S3 of -0.5. Estimate curl G at the point (4, 8, 8). curl G ≈