[Ádám] participates in a competition called KöMaL. It’s a 9-times-a-month journal for junior high and high school students featuring math and physics problems. [Paul Erdős], one of the most published mathematicians of all time, was a huge participant and by far the most notable student to crack open a copy of KöMaL in its hundred-year history. [Ádám] was trying his hand at a problem in Excel, but the official rules prohibit the use of Excel macros. In a daze, he came up with one of the most clever uses of Excel: building an assembly interpreter with the most popular spreadsheet program.

This is a virtual Harvard architecture machine without writable RAM; the stack is only lots and lots of IFs.  The instructions – mostly load, MOV, JNZ, INC, and CMP solves this problem, examining two inputs to see if they multiples of each other. If you’re wondering, an example cell from [Ádám]’s Excel sheet looks like this:

=F6
   INDEX($C$2:$C99999,$G2,1),
   IF(AND(INDEX($B$2:$B99999,$G2,1)="JZ",$I2=0),
      INDEX($C$2:$C99999,$G2,1),
         IF(AND(INDEX($B$2:$B99999,$G2,1)="JNZ",$I2<>0),
         INDEX($C$2:$C99999,$G2,1),
         G2+1
         )
      )
   )
)

[Ádám] has provided his Excel solution to the problem, available on the hackaday.io. It’s in Hungarian which really shouldn’t matter since it’s basically Excel and a pseudo-x86 instruction set. but the column labels will require a bit of Google Translate.