Here's a better example (found at slashdot), not obfuscated code but underhanded code.
Its purpose (and it does do this) is:
	Can you tell what this code does, HC?
	
		
	
							
						
					Its purpose (and it does do this) is:
read a PPM file in ASCII (P3) format, scanned over the numbers, and zeroed out the redacted pixels in the most obvious way possible:
Code:
	
	for(c = buf;*c;c++) {
          if(isdigit(*c)) {
                    if(!ws) {   // new number, increment location.
                              ws = 1; x++;
                              if(x >= width * 3) {
                                        y++; x = 0;
                              }
                    }
                    if(x > rx * 3 && x <= (rx + rwidth) * 3 && y > ry && y < ry + rheight)
                              putchar('0');
                    else
                              putchar(*c);
          }  else {
                    ws = 0;
                    putchar(*c);
          }
}
Spoiler: 
	
 ACK!
							
						
							
						
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