/* http://sedcore.eu.org/kronecker.c
 * version 2026-05-18
 *
 * Compile like this:
 * gcc -std=c89 -o kronecker kronecker.c
 * 
 * A little proggy to display the sierpinsky triangle on the terminal
 * computed using the nth Kronecker power of matrix G2 where G2 is:
 *       | 1 0 |
 *  G2 = | 1 1 |
 *
 * This is an easter egg found in the 3GPP document 38.212, in 5.3.1.2
 * (Polar encoding). The sense of humor of those corporate people never
 * ceases to amaze me.
 *
 * A coding style reflecting the clarity of the 3GPP specifications has
 * been employed. I think it is reasonably well accomplished.
 *
 * Todo: have 'putchar' appear only once and remove '\n' and ".*", which are
 * obvious deviances from the goal of compliance with 3GPP clarity. That
 * would enlight the reader even more!
 */

#define                            N                                       5
                                  main
(_,__,____,___,_____,______){    return     _||__!=4||!____?__>>=1,!_&&!__&&

main(_,main(_,4,4,main),main)&&main(_,main(_,4,1),__,main,main)||!_&&__&2||!
_&&__&1&&                                                          ____<main
(_,__+__+                                                          __+__,__-
__)<<N+N&&                        main                             (-main(_,
__+__+__+                                                          __,N,main
),main(_,                                                          main(_,__
+__+__+__,__+__,main,main),N),main(_,__+__+__+__,__+__+__+__+__+__+__),__,_,
____)&&main(_,main(_,__+__+__+__,__, main ),____+__)||_>_-_&&main(_-_,_-_)&&

                                 putchar

    ('\n')||!__&&(_____-______||(_____%-_||putchar('\n'))&&putchar(".*"[
___]))||main&&!_||main(_,__,main(_,__,main(_,__,main(_,__,main,___,_____+__-
__*_,______),___,_____,______),_-_, _____+__,______),___,_____-__*_,______):
           main(_,__,____-1,main)+main(_,__,____-5+__,main,

                                  main

                                  );}