to improvise:

from latin improvisus – unforeseen – to invent or make something, such as a speech or a device – at the time when it is needed without already having planned it.

to compose and perform or deliver without previous preparation.

to extemporize or to improvise an acceptance speech.

to compose – play – recite  or sing (verse – music – etc.) on the spur of the moment.

two piano improvisation:

an improvisation tradition established by jack hurst + bruno de florence – circa 2006 –  while studying at goldsmiths college – london – uk.

quoting j+b:

we do not agree on anything – nor theme nor duration nor colour nor rhythmic  nor harmornies nor when to stop – we just sit at our pianos and start – at some point we finish – simplicity always wins -

nota: please make the effort of listening to our playing either on decent headphones or by connecting your comp to a decent stereo system –  avoid listening through your comp speakers!

of note among their output:

marble arch-part 6c – australia-part 2 – australia part 4 – south kensington part 2