The square sheet is folded three times: first the top half is folded down along the horizontal centre line, then the left half is folded over the right half along the vertical centre line, and finally along a diagonal. The result is a right-angled triangle that is one-eighth of the sheet. In the final triangle there are three cuts: a small triangular notch at the right-angle corner (this corner is the middle of an outer edge of the sheet), a small hole near one acute vertex (this vertex is the centre of the sheet) and a small hole near the other acute vertex (this vertex is a corner of the sheet). On unfolding, each cut is reflected across the diagonal, the vertical line and the horizontal line, so the pattern becomes symmetric about both centre lines and both diagonals. 1. The notch at the middle of each outer edge appears as a pair of small triangles on each of the four edges. 2. The hole near the centre is repeated 8 times, forming a ring of 8 holes around the centre. 3. The hole near the sheet corner is repeated 8 times, giving 2 holes near each of the 4 corners. Only option (2) has triangles at the middle of the four edges, 8 holes around the centre and a pair of holes at each corner. Option (1) has holes instead of triangles on the edges, option (3) has triangles at the corners and option (4) has triangles at the centre. Answer: (2) the pattern with edge-middle triangles, a ring of 8 holes at the centre and 2 holes at each corner
