#include <stdio.h>
#include <string.h>

#define BUFSIZE 100

const char *message =
"          "
"Mr. Watson, come here. I want to see you."
"          ";

char buffer[BUFSIZE];

typedef unsigned char byte;

byte next_LFSR() {
    static byte LFSR = 0xFF;
    byte a = (LFSR & 1 << 3) >> 3;
    byte b = (LFSR & 1 << 4) >> 4;
    byte c = (LFSR & 1 << 5) >> 5;
    byte d = (LFSR & 1 << 7) >> 7;
    byte n = a ^ b ^ c ^ d;

    LFSR <<= 1;
    LFSR |= n;

    return LFSR;
}

void setup() {
    strncpy(buffer, message, strlen(message));
}


int main() {
    setup();

    int len = strlen(message);
    int j = 0;
    for (int i = len; i < len + len; i++) {
        buffer[i] = buffer[j++] ^ next_LFSR();
    }

    printf("%s\n", buffer);
}