樂譜上的「很快」
這一支最貼近義大利文原意。快就是快，沒有比喻，只是被寫進了譜裡。
adjective · C1
In music, played or sung at a very fast speed. It is one of the Italian words written on a piece of music to tell the players how fast to take it.
急板的；極快的
核心畫面
One way to hold presto: something going past so fast that the middle of it never reaches your eyes. On a page of music that speed is an instruction — take these notes at a run — and the fast movement itself ends up wearing the name. Push the same speed a little further and you stop being able to follow it at all: the hand moves, the coin is somewhere else, and the only honest report is that it happened. That is the shout at the end of a trick, and it is also what you say when a machine does in one second what you expected to take ten.
presto 可以想成一個畫面：東西跑得太快，中間那段根本來不及進到你眼睛裡。在樂譜上，這個快是一道指令——這幾行音…更多收起
presto 可以想成一個畫面：東西跑得太快，中間那段根本來不及進到你眼睛裡。在樂譜上，這個快是一道指令——這幾行音符要用跑的；跑得快的那段音樂，後來乾脆就叫這個名字。再快一點，你就完全跟不上了：手一動，硬幣已經不在原處，你只能說它發生了。那一聲喊出來的 presto 就是這樣來的。機器一秒鐘做完你以為要十秒的事，用的也是同一個畫面。From the word’s history
English took presto straight from Italian presto, meaning 'quickly'. Both branches in English keep that one word: the musical instruction is the plain meaning, and the magician's call is the same speed pushed to the point where it looks impossible.
英文的 presto 直接借自義大利文 presto，意思就是「快」。英文這兩條線都還握著這個字：樂譜上的用法是它字面的意思，而魔術師喊的那一聲，是同樣的快被推到看起來不可能的地步。
Wiktionary entries for presto (adv/intj/noun), source_ref kaikki:3f6f69a190036ae4:442355278 and :442356752 — "From Italian presto ("quickly")."
Two branches
快到像變出來的
同樣是「快」，但快到過程不見了。這一支不是從音樂延伸出來的，而是跟音樂並排、各自從義大利文的「快」長出來。
interjection · B2
Said at the moment something appears, changes, or is finished all at once, as if by magic. You use it to point at the result and to show that the middle part happened too fast to see.
瞧！變出來了