c - An Abstrusing printf() expression -

while reading random code, happen encounter printf() expression bit strange me, statement this

void printdiceface(int n){     printf("%d 0 %d\n%d %d %3$d\n%2$d 0 %1$d\n\n",n>50,51%n%2,n>53,n%2); } 

this obfuscated version of snippet prints face of electronic dice. example.

please explain printf() statement in detail.

http://en.wikipedia.org/wiki/dice

the format results in:

<num1>    0   <num2> <num3> <num4> <num3> <num2>    0   <num1> 

with numbers being either 0 or 1 depending on result of operations later on. unusual thing in format string use of %<n>$ - says parameter, arg<n> of function (instead of 'the next' in order) should used. example, if specify:

printf("%d %1$x\n", 10); 

it prints '10 a'.