Location: Page 36 in the book/pdf, page 17 in the Ch 2 Google document (now fixed in the doc), it was stated that "These 4 elements make up the 3rd and last dimension of this matrix since there are no more inner brackets." We incorrectly said "matrix" here. This should be "array." A matrix is a 2D container, and the object in discussion was a 3D array.
Page 42 in the book/pdf, top of page 23 in the Ch 2 Google document (now fixed in the doc), it was stated that "The dot product’s result, in our case, is a vector (or a list) of sums of the weight and bias products for each of the neurons." We incorrectly said "weight and bias" products, when we meant to say "weight and input" products. Weights and inputs are multiplied, not weights and biases.