fn letter(character: char) -> [u8; 8] {
    match character {
        'a' => [
            0b01111110, 0b01000010, 0b10000001, 0b11111111, 0b10000001, 0b10000001, 0b10000001,
            0b10000001,
        ],
        _ => [0; 8],
    }
}