I corrected last line to compensate 3-cycle overhead for every frame and also fixed order of patterns at the bottom of the screen - perfect version to burn my 1st OTP MCU :)

Final version is 445 words long (87% of PIC12C508) and available on GitLab

Source code also has schematics in it as a comment:

;       +5V
;      .--*
;      #  |  PIC12C508
; 470* #  |   ---v---
;      #  \--|1     8|- GND
;      | NC -|2     7|--###-\  1.5 kOhm
; SYNC *-----|3     6|--###--* 680 Ohm
;      | IN -|4     5|--###-/| 330 Ohm
;      |      -------        |
;       ----------------###--*---> VIDEO (8 gray levels)
;                     1 kOhm

UPDATE: Another 2 TVs running by OTP PC12C508A, both SONY - big CRT one (4:3):

and big LCD one (16:9):

with video :)

As you can see last few shades (5,6,7) are too bright and looks all white (may be because of 1.5V max amplitude). Also there is a space for 48th column on the left side - I'll add it in the next version that will be re-written for heavy macros usage to represent repeating code for visibility purposes...