}
    }
    return count;
}

void aoc202507(char *data, size_t len) {
    (void)len; // unused argument
    struct RectangularMap rm[2] = {0};
    while (*data) {                      // copy from data to rms
    struct RectangularMap rm[1] = {0};
    while (*data) {
        char *data2 = data;
        while (*data != '\n') data++;
        *data = 0; // erase newline
        RMaddline(rm + 0, data2);
        RMaddline(rm + 1, data2); // set both rm's to the same thing
        *data++ = '\n'; // unerase newline (obviously!) and skip it
    }
    unsigned part1 = tachyon_splits(rm);
    printf("P1: %u\n", part1);
    RMfree(rm);
    RMfree(rm + 1);
}

/* === aoc202506 =======================================================
===================================================================== */
static long long unsigned add2506(long long unsigned v[4][1024], int lin, int col) {
    long long unsigned sum = 0;
    for (int k = 0; k < lin; k++) sum += v[k][col];