Spinning Quine Update After completing this page/project I did a web search for my spinning quine page. It turns out, someone else had a very similar idea. They made a "spiraling" quine in perl. I guess great minds think alike ;-). Any ways, here is a link to the page with the spiraling quine. It is a lot different than mine, because they made use of perl's ability to evaluate a string as code. Something you can't do in C (unless you write your own interpreter). So, the code ends up being much smaller. Introduction After completing a simple quine, I decided to try something a bit more challenging. The result is the following iterating quine. An iterating quine is a program that outputs the source code of another program. The new program can then be compiled, and it outputs the source code for another program. This process can be continued until eventually the n'th program outputs the original program. Here is the source code for the first program in the sequence. If you look at the sequence of programs generated, the spiral of text in the array can be seen "spinning" clock-wise. Source: spinningquine.c char r[]= " - SPIRAL - A~G w 77AG h 24A " " an Iterating Quine x+y*w];}AR i{F x,y;F p;E c;} G s (w* " " by Dave Cope ){L &p[ ;A}AF *x=&i->x;AF *y=& p[2];A h)AG " " x,E y =1.0f;AL v;Ai->c++;A}AK q(N i->y;AF E ix( m 96 " " p,E Ai->y x=u;A*y= s);Ap[0].c=p *p)A{A u=*x F x) 4AN " " a(N* .0f; ));A* ];AH(b,r, q(b) [1].c=m; E i=0 ;AF {L( *d[ " " N* x=0 (*y b[s 0].y));A}A ;AM(B;CnB) At(1) ;AD; v=*y E)( ]= " " ;AA i-> =iy 0;AN iy(p[ ,ix(p[0].x),iy(p[0 ;A}AE ;AD; i<s ;A (x A{ " " A} p= v)= i= x), =*a(r .y));ATc>=65&& ].y) O( i< ;i F +1 A " " B, -> y( AE 0]. ;Ac p[0] c<=9 );A )A =m ++ a; .0 BC " " U Ai &i A{ p[ 0) iy( 0) }Q {A +1 )A AS f) n " " AB ; & ) ( ( ), M( c! E 0 { A * B, " " , 1 ) ( x t x. A} [d 1= ; A { /w BA " " BT =c x* v i, A{ ]0 A; 6-c 62 =i +i E iA 2 C " " BA >- (x KA r( SA [p( 0 LA}A; PA;)]5 QA;) A;m )+ =t >- ;) BB " " ,B iA i= }A a*= ;m=c xi,r(a )c(U {A)i-- ;c N A{A w%i p A} A, " " SB {A =)u }A; ))y. .]0[pA *=cA;)0(tA NB(MA )0(t TA; =+ i E CB " " A,B ) m (xi )BnCB ]1[p(y ;)(vA;)BnC=][r )1(tA; t! 00.0 F(y ,BC " " RBA == Q}A; CB(MA i,)x.]1[p(xi,b(a*A; B'(UA) A;f1 )y DBA " " ,BQB c>-i )p>-i( ))1-w(==tTA;)]i[p(UA;)' 36(=a )E(L{ BA,B " " A,BP TA;]b J*a=vA;)p>-i( uA;36/)p>-i - f0.1(( BA,BE " " BA,BOB [p&=i* i R I*a= };)2/h*)y- GBA,BF " " A,BNBA,BM A{A) b E (t KA BA,BHBA,B " " BA,BLBA,BKBA,BJBA,BI " ; #define w 77 #define h 24 #define s (w*h) #define m 964 char *d[]= { "

", " \" ", " \\ ", " for( ", " int ", " float ", " #define ", " memcpy ", " sin ", " cos ", " void ", " return ", " printf ", " char ", " main ", " else ", " while( ", " struct ", " do ", " if( ", " putchar ", }; char *a( char *p, int x, int y){ return &p[x+y*w];} struct i{ float x,y; float p; int c;} p[2]; int ix( float x){ return ( int )((x+1.0f)*w/2);} int iy( float y){ return ( int )((1.0f-y)*h/2);} void t( int b ) { struct i *i=&p[b]; if ( i->c == m ) { i->c=1; i->p=i->x=0.0f; i->y=1.0f; return ; } float *x=&i->x; float *y=&i->y; float u=*x; float v=*y; float a; do { i->p += 0.001f; a=(63 - i->p)/63; u=a* sin (i->p); v=a* cos (i->p); } while (ix(u)==ix(*x)&&iy(v)==iy(*y)); *x=u; *y=v; i->c++; } void q( char *p) { int i=0; for (;i<s;i++) { int t=i%w; if ( !t ) putchar (' " '); putchar (p[i]); if (t==(w-1)) printf (" \"

"); } } void v() { int i=0; char b[s]; memcpy (b,r,s); p[0].c=p[1].c=m; t(1); for (;i<=m+10;i++) { t(0); t(1); *a(b,ix(p[1].x),iy(p[1].y))=*a(r,ix(p[0].x),iy(p[0].y)); } q(b); printf (" ;

"); } int main() { int i=m; char c; printf (" char r[]=

"); v(); p[0].c=m; do { t(0); c=*a(r,ix(p[0].x),iy(p[0].y)); } while (c!=126); while (--i) { t(0); c=*a(r,ix(p[0].x),iy(p[0].y)); if (c>=65&&c<=90) printf (d[c-65]); else putchar (c); } return 0; } Note: The source code in the figure above has been indented. Take a look at the original source to see the unmodified formatting.