Inaccuracy in my answer in "History" on Morse Code. It IS used visually with flashing lamps or a single flag.?

Used by UK military ships using Aldis lamps. Very fast and not easily overheard by the enemy from afar.

The Code's utility is that it can be transmitted by a variety of means. However, semaphore - the sending of messages by using flags - does not involve the Morse Code. Nowadays about the only time you'll ever find the Code being used to transmit messages is in Amateur (ham) Radio. Newer technology has made sending messages much simpler, faster and infinitely more reliable. Proficiency in sending and receiving Morse Code used to be required in order to get your ham radio license, but that requirement was dropped several years ago. Hams now use it for personal communication with other hams, just for the fun of it. I can still send and receive at about 13 words a minute, and that's enough for me. When I'm on the air (both my wife and I are hams) I rarely use it anymore.

Flashing lamps yes, a single flag possibly and also a mirror.

It can be transmitted by flashing lamps or by telegraph. Short flash for dot, long flash for dash. Flags are used in semaphore not Morse.Different system.