/* CLAB / 2023 / LT2 */

#include "common.h"
#define RECIPROCAL_SQRT_2 0.7071067811865475

int main(int ac, char *av[])
{
    float a_x, a_y, b_x, b_y, mid_x;
    float radius;

    scanf("%f %f %f %f", &a_x, &a_y, &b_x, &b_y);
    if (a_y != b_y) {
        printf("INVALID INPUT\n");
        return 1;
    }
    mid_x = 0.5 * (a_x + b_x);
    radius = fabs(a_x - b_x) / 2;
    radius *= RECIPROCAL_SQRT_2;

    printf("%.3f %.3f\n", mid_x - radius, a_y);
    printf("%.3f %.3f\n", mid_x - radius, a_y + radius);
    printf("%.3f %.3f\n", mid_x + radius, a_y + radius);
    printf("%.3f %.3f\n", mid_x + radius, a_y);
    
    return 0;
}