Good morning everyone!
Wah.. so much discussion over Adrian's pics.
Actually hor, I think the curvy ones are ACCURATE. hehe
The fireworks are basically red-hot pyrotechnic particles blasted into the air. The curvy paths are them tumbling to the ground. Sorta between a feather and a ball, if you know what I mean. So...I think it's your friend's camera that has smoothened the lines too much. Maybe the JPEG output too aggressive?
hehehe that's what I think anyway.