[Coco] Program for test pattern for crt alignment/convergence?

[Don Barber]

Hi folks, acknowledge I'm sending a lot to the list recently but I got a 
lot of projects going on.

I'm replacing the tube of a Commodore 1084S-D1 when the old crt tube 
'let the vacuum out.'
I've got it aligned pretty close by eye but to get it exact I'd like a 
proper test pattern, like white-on-black grid lines to get it just 
right. I've already soldered up the cable to get this monitor working on 
the coco so was hoping to be able to generate such a test pattern from 
the coco.

As such, anyone know of a coco program to generate decent test patterns, 
specifically a grid / cross-hatch pattern?

I found Coco Color Bars ( 
https://colorcomputerarchive.com/repo/Disks/Demos/Coco%20Color%20Bars%202020%20(Jason%20Reighard).zip 
) which is awesome - but still looking more for the grid test pattern. 
Figure I could probably whip something out in basic without much effort 
but thought maybe someone would know of an existing one?

Alternatively I could probably get a CGA cable together to hook up this 
monitor to an early PC if someone has an early dos program to generate a 
test pattern.

Don