Acapela is... a-cape-for-Bela, and a box.
It is composed of two things, a circuit board and a box (or enclosure). The circuit board has space for eight potentiometers and two 1/8" TRS (a.k.a. mini-jack) connectors for stereo audio input/output. It attaches directly on top of Bela. The box just keeps everything together and makes it easier to move around.
The definition of a spectrophotometer is an instrument used to measure the intensity of wavelengths in a spectrum of light. An example of spectrophotometer is how an ink manufacturer would figure out how much of one color is present in an ink.
This is a fidgetspinner made from 3mm HDF, a small ballbearing from a 3d printer, and 3 steel balls from a bigger ballbearing. It is made for assembly without glue.
Remember to change the center hole for your bearing size.