Not that they were available very widely in the 1950s. These cool blocks were designed for use in Danish schools and as such, were never commonly seen or indeed, played with. But that's not the case now, with the blocks available for play, learning to read or indeed, for adults to show off their designer credentials with a box on display.
Talking of which, they are sold in the box pictured here, which contains 33 curved blocks and 33 straight blocks and yours for a price of €79.95.
Via Junior Hipster