Seek helps with letter-number task switching test

If this template helps then use it. If not then just delete and start from scratch.

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): 2020.2.10
Standard Standalone? (y/n) If not then what?: Y

What are you trying to achieve?:

I want to design a number-letter switching task to measure cognitive flexibility. The basic idea is that the participants tell consonant/vowel or odd/even of stimuli. The stimuli is a combination of a letter and number like A7. In the letter task, they need to choose vowel by pressing “N” because it is “A”. In the letter task, the participant should choose “odd” by pressing “B” because it is 7.

The stimuli are presented in four quadrants. During the letter trial, the letter-number combination always appeared in the upper two quadrants. In the number trial, the stimulus is in the bottom quadrants. The combination is always presented in clockwise order, quatrants1 (topleft) → quatrants2 → quatrants3 → quatrants4.

I have 64 variants of unique letter-number combinations in excel as a column.

My question is how to achieve this. How to handle different letter-number combination stimuli for each trial and also the position. Also I could I capture the response time (press the key)?

What did you try to make it work?:
I create 4 loops for each quadrant, which contain the condition excel and 1 global loop for the whole four trails which contain no condition.

What specifically went wrong when you tried that?:

Now what I can get is the stimuli can show up in a right sequence. But in each quadrant it will repeat showing for 64 times. I just want a stimuli to show just once and move to next quadrant.