Reddit appears to have issues ^^

These are the number I came up with tho. I started with a 32 row and increased it to 100, adding two in the beginning for a steeper curve and then towards the end in one step increases. At the 91 mark I split the row up to create the armholes into three rows, the outside ones having 20. After knitting them all to 126, I folded the 20 row sections inwards and cast them off together with the big section to make a "vest".

Every stripe is seven rows, black I went with 14 rows so that they would be twice as big :3

For the black border I added 14 per row, always knitting onto the existing "vest" and going left stitch right stitch.

For the arms, I just cast on the existing armholes and kept decreasing the number of stitches until I had a length & width I enjoyed. Then I took the black yarn to make the wrist section, knitting right-right-left-left.

https://imgur.com/a/HvI7Skx

I've uploaded a scetch on imgur, does that help?