"Reinventing the square wheel is the practice of unnecessarily engineering artifacts that provide functionality already provided by existing standard artifacts (reinventing the wheel) and ending up with a worse result than the standard (a square wheel). This is an anti-pattern which occurs when the engineer is unaware or contemptuous of the standard solution and also does not understand the problem or the standard solution sufficiently to avoid problems overcome by the standard. It is mostly an affliction of inexperienced engineers." [link]

Another one for Livius's blithering idiom contest: [link]

I decided to be lazy and inexperienced engineer, so I left some usual car parts like steering wheel and brakes off.

I had plans to make it like shoe to combine it with another idiom "car boot sale", but I left that idea out. Shape still resemble shoe. Also "car pool" was in mind, but that idea went to trash too. Pool would have made this emote too big.