Drawing the screen using plot and unplot blind, need help

[Crayon21]

Any tips for me? I read the manual. The manual says there are 704 positions but never gives a grid like in other manuals for reference, so I have no idea where to start. Unlike the ZX Spectrum's UDG examples, the zx81 manual doesn't have a grid with the numbers on it so I can easily reference it. This means I am plotting blindly.

The Grid would look like this:

X X X X X X X X
X X <==
X X
X X X X X X X X

the zx81 on the other hand is one big question mark. I don't know where to plot anything.

Whereas on the spectrum I'm looking at this

^
On the zx81, it's this:

?
?
?
?

you see the issue?

(the grid isn't showing correctly, sorry for that, nothing I can do.)

[1024MAK]

Last page of chapter 18 in the ZX81 BASIC Programming manual.

See here (scroll down and click on chapter 18 on the left side, then when that page opens scroll to the bottom of the web page).

Top (columns) and left (lines) are the character cells. Bottom and right are the pixel coordinates.

Mark

[Crayon21]

thank you

[XavSnap]

Crayon21, Have a look to this thread:
https://www.sinclairzxworld.com/viewtop ... 178#p34178