Exercise 2 solution

    import os, tempfile

    values = [1, 256, 65535, 1000]
    path = os.path.join(tempfile.gettempdir(), "u16.bin")

    with open(path, "wb") as f:
        for v in values:
            f.write(v.to_bytes(2, "little"))

    with open(path, "rb") as f:
        raw = f.read()
    print(raw.hex(" "))                  # 01 00 00 01 ff ff e8 03

    little = [int.from_bytes(raw[i:i + 2], "little") for i in range(0, len(raw), 2)]
    big = [int.from_bytes(raw[i:i + 2], "big") for i in range(0, len(raw), 2)]
    print(little)                        # [1, 256, 65535, 1000]
    print(big)                           # [256, 1, 65535, 59395]
    print(little == values)              # True
    os.remove(path)

(Run as written; the output matched the comments.)

Explanation: each value takes two bytes, low byte first. 1 is 01 00, 256 is
00 01, and 1000 (0x03e8) is e8 03. Reading the same bytes as big-endian swaps
the two bytes of every pair, so 1 becomes 256, 256 becomes 1, and 1000
becomes 0xe803 = 59395. 65535 is ff ff either way, which shows why a wrong
byte order can go unnoticed on symmetric values.