How to generate k+1 length strings from a list of k length strings?

[Boris Borcic]

bearophileHUGS at lycos.com wrote:
> Boris Borcic:
>> I'd favor the following, that I find most readable
>> sets = map(set,list_of_strings)
>> res = set(''.join(sorted(s1|s2)) for s1 in sets for s2 in sets if len(s1^s2)==2)
> 
> I think there can be written more readable code.

readability, of course, is in the eye of the beholder... and I find this code 
*much* easier to recognize as a realisation of the description made by the OP, 
than the code he himself offered - if you care to take a look at both.

For my programs I
> usually prefer simpler code, 

I challenge you to write simpler code to do the equivalent.

 > that (if possible) even a children can
 > understand.

what child ? one that is trained just like *you* think children should start, I 
guess.

 > So I can debug, modify and improve it better & faster.

Sure, but the case is we each were *distinct* children.

> 
> Bye,
> bearophile
>