* Delete:
1 16 17.5 -.25 17.5 1.5 0 0 0 1 0 0 0 1.5 1-4ndis.dat
it's no longer needed
* Add some empty lines above the cilinder prims to make some room for them
* Add the comment "0 // Thin box" to document your code a bit
https://www.ldraw.org/article/218.html#lt0
* Select the three cylinder prims, color them with 16 - Main color
* Copy & paste them, convert them to chord prims and start building the bottom of your sticker box
* The "problems" pane might warn you at some point about:
"The flat subfile is scaled in Y direction."
try figure out why.
* Draw quads between the cylinder prims. This is actually bad style 'cos it creats T-Junctions:
https://wiki.ldraw.org/wiki/T-Junction
on the other hand there is a clear edge and using tringles to connect all the vertices would result in long, stretched triangles - already mentioned above.
* Build also the bottom of the sticker with quads.
Screenshot
LEGO ergo sum