quattro[Moderator]
19829
Patek Philippe's “Padellone” case
Designed in 1962 by the Antoine Gerlach manufacture, the case of the ref. 3448 (the very first self-winding perpetual calendar made by Patek Philippe) was nicknamed the "Padellone", Italian word for "frying pan".
It can be found, with minor modifications, in three other references, which I happen to like quite a lot: 3450 (which I like a little less to be honest), 5235 & 5236.
Here's an overview: enjoy!
A/ Ref. 3448 (cal. 27-460, 37.5mm case)
1/ Yellow gold

credit: amsterdam vintage watches

Alan Banbery’s unique ref. 3448J ‘No Moon Phase’ with Phototype Leap Year Indication (credit: christie’s)
2/ Rose gold (this is the only known rose gold example, which comes with a unique "double P" crown)
3/ White gold

credit: hodinkee

Only known ref. 3448 with Leap Year Indicator, a specificity of the ref. 3450. White gold. (credit: hodinkee)
Ref. 3448 ”Senza Luna": one of six known pieces without a moon phase (credit: William Massena on TimeZone)
4/ Platinum (there was originally no platinum 3448, but, in 1997, Philippe Stern approved the assembly of two 3448s in platinum cases, using previously cased movements from the 1960s)
Property of Jean-Claude Biver (credit: hodinkee)
Ref. 3448/100 from 1973 with sapphire-set indexes (cased in platinum in 1997). It was sold at a 2021 Hong-Kong Auction (credit: phillips)
B/ Ref. 3450 (cal. 27-460QB, 37.5mm case, leap year indicator between 3 and 4 o'clock)

credit: christie’s

credit: reddit

credit: the keystone
Variant with Roman numerals & needle hands (credit: WatchTime)
C/ Ref. 5235 Annual calendar regulator (cal.31-260 REG QA, 40.5mm case)
1/ White gold ref. 5235G-001

credit: the keystone

credit: Sjx

credit: a collected man