Fig.: to be a small version of the original

This very young athlete is becoming a world class diver, like his father twenty years ago. We may well say that he's a chip off the old block

Questo giovanissimo atleta sta diventando un tuffatore di classe mondiale, tale e quale a suo padre vent'anni fa. Si può proprio dire che è il degno figlio di suo padre

His father was an Oscar winner, his mother an excellent Broadway actress, but when he tried to act himself, it was a disaster, certainly not quite a chip off the old block

Suo padre era un attore da Oscar, sua madre un'eccellente attrice di teatro, ma quando anche il figlio ha tentato la strada dello spettacolo è stato un disastro, certamente non degno del proprio padre

Until recently "of" rather than "off", this expression, dating back to 270 B.C., is attributed to the Greek poet Theocritis, who wrote, "a chip of the old flint" in the poem "Idylls".
The first form of the expression was chip of the same block, meaning that a person or thing was made of the same stuff as somebody or something else, so from the same source or parentage. An early example of its use is in a sermon by Dr Robert Sanderson (at one time Bishop of Lincoln), dated 1637: "Am not I a child of the same Adam... a chip of the same block, with him?".