A drum technique in which four beats of equal length are played, in one of two combinations:

• Left stick, Right stick, Left stick, Left stick
• Right stick, Left stick, Right stick, Right stick

If more than one paradiddle is played, then the two options above are normally alternated between. For beginning percussionists, this can be a challenging thing to play at high speeds.

R-L-R-R-L-L R-L-R-R-L-L

Like any paradiddle, they can be inverted:

L-R-L-L-R-R L-R-L-L-R-R

Played very fast, these make for neat, jazzy fills, and they can form excellent 3/4 beats if divided into two groups of three beats rather than three groups of two. This division can be conveyed to listeners by using the bass drum at the beginning of every triple (hits played simultaneously with the bass drum indicated by parentheses):

(R)-L-R-(R)-L-L (R)-L-R-(R)-L-L

This too can be inverted.

Paradiddles, like all percussion rudiments, are absolutely essential to the proccess of becoming a respectable percussionist.

And Beltane, below, is absolutely right -- his "inversion" is much more interesting than mine is. Use paradiddles for texture in your fills, if you're a drumset player. They're more interesting if you vary which note you accent (this is very hard) and make a more virtuosic alternative to the single-stroke roll.

An actual inverted "triple paradiddle" or paradiddle-diddle more literally, is not a paradiddle-diddle off the left hand. An inverted paradiddle-diddle would actually be the inverse of its regular form:

Para-diddle-diddle in sixlet form:

RLRRLL RLRRLL RLRRLL RLRRLL
LRLLRR LRLLRR LRLLRR LRLLRR

Inverted Paradiddle-diddle:

LLRRLR LLRRLR LLRRLR LLRRLR
RRLLRL RRLLRL RRLLRL RRLLRL

Often times the first note of a paradiddle-diddle is accented.