Practice PAT #8, Question 57
While infrequent, you may encounter inward folds in the PAT hole punching section. The solution explanation for q.57 represents inward folds as red arrows and outward folds as blue arrows, as shown below:
You may be wondering what an inward fold is. Most folds in the hole punching section are made outward, or "out of the screen." However, an inward fold moves the paper "into the screen." As a result, part of the paper will be hidden from the viewer.
For q.57, fold 4 is an inward fold. The crease of this fold is made along the red dotted line (see below). The blue arrow represents the inward fold, where the left side of the paper is folded underneath the right side (see below). The green dotted line represents the edge of the paper that was previously on the left side before it was folded underneath the right side (see below). Even though the green edge is not directly visible, the hole punch in the top right corner punches through the green edge to produce a half-punch.
As we unfold this pattern along the red crease, the half-punch folds back to the top left corner, resulting in an extra hole.
Practice PAT #8, Question 58
Folding one piece of paper over another produces two layers, you might assume that a hole punch will automatically create a hole in both of these layers. However, this is not always the case.
There are two situations where only one layer is hole punched:
Bottom layer extends past top layer: Here, it is easy to see that a hole punch might not produce a hole in the top layer. For example, a hole punch in the red location will not produce any hole in the yellow layer (see below).
Top layer extends past bottom layer: This is less obvious to visualize, but it is essentially the same situation as point 1. Imagine flipping the pattern below upside down. Now, the yellow layer is the bottom layer and the the hole punched layer is the top layer.
For q.58, the edge of the bottom layer is labeled in green (see below). When the paper is folded along the orange crease, the top layer extends past the bottom layer so that only the top layer exists in the location where the blue hole is punched (see below). After we unfold the paper along the orange crease, the area that was originally hole punched is indicated with a dotted blue circle (see below). No hole has been punched in the bottom layer and thus, no hole exists at this spot in the completely unfolded paper.