Question 1
A paper when unfolded shows four holes in a square arrangement at the center. What folding was done before the single hole punch?
Reverse Engineering Solution:
Step 1 - Reverse Problem Approach:
- Given: Final unfolded pattern
- Find: Folding sequence used
- Strategy: Work backwards from result
- Difficulty: Requires pattern recognition and process reconstruction
Step 2 - Pattern Analysis:
- Given pattern: four holes in a square arrangement at the center
- Hole count: 4
- Arrangement: square at center
- Symmetry: horizontal and vertical symmetry
- Hole positions: corners of a centered square
Step 3 - Hole Count Formula:
- Basic formula: holes = punches × 2^folds
- Here: 4 holes, assume 1 punch
- So: 4 = 1 × 2^folds ⇒ 2^folds = 4 ⇒ folds = 2
- Conclusion: 2 folds were used
Step 4 - Symmetry Analysis:
- Identify all symmetry axes in pattern
- Square pattern has: horizontal symmetry, vertical symmetry
- Each symmetry axis suggests one fold
- Two perpendicular symmetry axes = two perpendicular folds
Step 5 - Fold Sequence Reconstruction:
- Number of folds: 2
- Type of folds: perpendicular (horizontal and vertical)
- Order: could be horizontal then vertical, or vertical then horizontal
- Punch location: center (to create centered pattern)
- Result: Folded horizontally, then vertically (or vice versa) before punching center
Key Principles:
- Holes = punches × 2^folds
- Each fold adds a symmetry axis
- Pattern shape reveals fold directions
- Punch location determines pattern center