8 foot long shelf with a little twist

I just made this shelf using 2x4s 8 ft long wood. It is very strong and looks great. My garage size required the shelf to be max 16 in deep, so I used a 1 plywood sheet divided by 3 equal parts for the upper 3 shelfs. Since I made a 4th shelf, I used 3 1x2s for the 4th bottom shelf instead of a new plywood sheet and avoided having extra 2/3 of the sheet around and also saved like 30$ since the 2x1s were only 2$ea. That touch makes it look a bit stylish too so a win win. If you do that, here's a tip: use the outer 2x4s as rails - make sure that the cleats on the lower shelf are placed a bit lower ~ 1in. In such way, you can place the three 1x2 rails at the same level as the outer 2x4s and this you end up having 5 rails total in the shelf. Do use the wooden screws with star head if you can, they were muuuuuch easier to use compared with the regular ones. Note, this shelf is very strong, probably too strong for my needs. For a 8ft long, and my storage needs (camping, Christmas stuff, other lighter things), I'd probably use 2x2s instead of 2x4s. That would save costs, specially since wood isn't cheap these days( I spent ~$150 in materials Jan 2022).