Haven't posted in ages and wanted to ask some of the experts here if they could shed any light on the following:
Early Vibram Five Finger (SKU V5151574, for example) soles I think had "micro slots" (for want of a better term) which were closed when the sole was at rest, and opened when the sole was flexed.
I cannot find much evidence of this other than the below image. I've highlighted the area that might show an "open" area.
Current product now seems to have a much more common sole design:
I'm wondering how the sole of the original, particularly the "micro slots" were formed? Think most soles are compression moulded however I don't understand how the slots could be tooled, other than a secondary die-cut type process?