An installing hole forming mechanism includes at least one guiding sleeve and an inserting set. The at least one guiding sleeve includes a bore. The inserting set is detachably coupled to the at least one guiding sleeve and includes at least one spike configured to couple to the bore of the at least one guiding sleeve. The at least one spike includes a tip. When the at least one spike passes through the bore of the at least one guiding sleeve, the tip exposes from the guiding sleeve, and the at least one spike and the at least one guiding sleeve are forced to puncture a shoe such that at least one installing hole is formed on the shoe.

An installing hole forming mechanism includes at least one guiding sleeve and an inserting set. The at least one guiding sleeve includes a bore. The inserting set is detachably coupled to the at least one guiding sleeve and includes at least one spike configured to couple to the bore of the at least one guiding sleeve. The at least one spike includes a tip. When the at least one spike passes through the bore of the at least one guiding sleeve, the tip exposes from the guiding sleeve, and the at least one spike and the at least one guiding sleeve are forced to puncture a shoe such that at least one installing hole is formed on the shoe.

A method of manufacturing a midsole for an article of footwear includes cutting a pattern of openings at least partway through a midsole with a cutting tool driven by an embroidery machine. An article of footwear includes a midsole defining a pattern of openings extending at least partway through the midsole. An inner surface of the midsole is contoured and the midsole includes upwardly-extending sidewalls. At least some of the openings extend relatively nonparallel with one another through the sidewalls and splay away from one another along longitudinal axes of the openings.

A method of manufacturing a midsole for an article of footwear includes cutting a pattern of openings at least partway through a midsole with a cutting tool driven by an embroidery machine. An article of footwear includes a midsole defining a pattern of openings extending at least partway through the midsole. An inner surface of the midsole is contoured and the midsole includes upwardly-extending sidewalls. At least some of the openings extend relatively nonparallel with one another through the sidewalls and splay away from one another along longitudinal axes of the openings.