User Instructions
1. Select Solder Amount: Toggle between "Optimal", "Excess", and "Blob" to see how the shape changes. Notice how excess solder creates a convex "ball" shape.
2. Identify Cold Joints: Click the "Cold Joint" button. Observe the dull, grainy texture. This happens when the soldering iron isn't hot enough or the joint moved while cooling.
3. The "Concave" Rule: A perfect joint should look like a small volcano or skate ramp (concave). If it looks like a ball (convex), it creates stress points and hides connection failures.