This is Popper's next problem.

hakank.
'''
Here's a new problem. It has the same structure as the previous one. Please don't output detailed analysis or Python code until I ask for it. Can you figure out the pattern?

pos(f([i, f, x, c, d, c],c)).
pos(f([g, b, c, d, x, b, i, j],b)).
pos(f([b,d,h,j, x, b],b)).
pos(f([h,e,g,h,j,c,x,g],g)).
pos(f([a,f,k,d,e,x,d,a,b,c],d)).
pos(f([a,e,d,x,f,a],f)).
pos(f([d,e,f,x,h,c,a],h)).

neg(f([c, d, i,j],d)).
neg(f([a, j, c,e, b,c,d],b)).
neg(f([c,e, i, a, b, b, a],e)).
neg(f([c,b,c,d,c,d,c,f],d)).
'''

GPT4:
'''
Based on the provided positive and negative examples, it appears that
the function f returns the element in the input list that comes
immediately after the first occurrence of the letter 'x'.

Positive examples:

    pos(f([i, f, x, c, d, c], c)) - 'x' is followed by 'c'
    pos(f([g, b, c, d, x, b, i, j], b)) - 'x' is followed by 'b'
    pos(f([b, d, h, j, x, b], b)) - 'x' is followed by 'b'
    pos(f([h, e, g, h, j, c, x, g], g)) - 'x' is followed by 'g'
    pos(f([a, f, k, d, e, x, d, a, b, c], d)) - 'x' is followed by 'd'
    pos(f([a, e, d, x, f, a], f)) - 'x' is followed by 'f'
    pos(f([d, e, f, x, h, c, a], h)) - 'x' is followed by 'h'

Negative examples:

    neg(f([c, d, i, j], d)) - 'x' not present
    neg(f([a, j, c, e, b, c, d], b)) - 'x' not present
    neg(f([c, e, i, a, b, b, a], e)) - 'x' not present
    neg(f([c, b, c, d, c, d, c, f], d)) - 'x' not present

In each positive example, the output matches the element immediately
after the first occurrence of 'x' in the input list, while in the
negative examples, 'x' is not present in the input list.
'''

I then asked for the Python progra (next.py)
'''
Here's a Python function that implements the described pattern. The function
element_after_x takes an input list and returns the element immediately after
the first occurrence of the letter 'x'.

 [Python program]

This Python code defines a function that finds the element immediately
after the first occurrence of 'x' in the input list and returns the result.
The test cases provided should produce the expected outputs based on the
problem's positive examples.
'''

Success!