#include <avr/io.h>
#include <stdint.h>
#include <util/delay.h>

void wait(void) {
	uint8_t i;
 	for (i=0; i<10; ++i)
		_delay_ms(25);
}

int main() {
	void wait();
	uint8_t c1, c2, i;

	DDRB=0xFF;
	while (1) {
		c1=0x80;
		c2=0x01;
		for (i=0;i<4;i++) {
			wait();
			PORTB=~(c1|c2);
			c1>>=1;
			c2<<=1;
		}
	}
	return 0;
}