Introduction
Germany 1996
Willem II 2002
Real Madrid 2003
AC Milan 2004
Chelsea 2004
Roda JC 2004
FC Utrecht 2004
Ajax 2004
Cameroon 2004
Italy 2004
Sporting 2004
Bayern München 2005
Schalke 04
Real Madrid 2005
FC Twente 2005
NAC/Vitesse 2005
Italy 2006
Netherlands 2006
Sevilla 2006

The Dutch national team plays in Nike shirts, so they wore the sausage numbers, the 'frikadel' numbers and the DIN-like numbers (see Nike). For the Worldchampionship 2006 Nike designed new shirts, based on designs from 1905 (away) and 1959 (home). The numbers on these retro shirts are inspired by (as Nike says) Dutch architecture, postage stamps and coins. Indeed they remind me of the stamps that Wim Crouwel designed in 1976 (known as 'cijferzegels'). His design was original at that time, but nowadays there are hundreds of fonts based on the same rectangular principle.
The Nike design for the Dutch team is absolutely obsolete, predictable and lacks originality. In my opinion it has nothing to do with good architecture nor with Dutch coins. You can’t even call this a design; it’s just an exercise with ruler and pencil.
Besides that: why should you seek inspiration in coins, stamps and architecture when you want to design shirt numbers??? The real inspiration lays in the football stadium. Look at the game, look at the players, look at their movements. A better source can’t be found.

PS. Besides the square numbers Nike provided the Dutch team with letters for the player's names. These letters look as if they are copied from a license plate. Some straight angles at the beginning or ending of a stroke are rounded.
Apart from the question if these letters are well designed (no, they aren't) it's obvious that they differ completely from the numbers. So, the Dutch shirts show a terrible combination of two failed type designs.

The new numbers of the Dutch team are inspired by Dutch coins, Dutch stamps and Dutch architecture, but they can also be reconstructed with Dutch toiletpaper.