Medieval cities were often somewhat impromptu in their structure. They grew semi-spontaneously, despite attempts to regularise them - for instance the bastides, grid-based towns around a central square, in southern France. (Winchelsea, a town founded by Edward I of England, is also a bastide, though it's almost a ghost town - it began to shrink once the sea receded and its port trade disappeared.)
But the Renaissance brought new ideas of architecture and in particular, the idea that towns and cities should be planned to create harmonious and functional spaces where citizens could function. The square was no longer just an area without buildings, and the street no longer simply a thoroughfare; components were given meaning and dignity.
So we see, for instance, the Place des Vosges and Place Royal in Paris being created; Michelangelo refocusing the scattered medieval buildings of the Capitoline Hill into a centralised, symmetrical composition and planning a pavement which would integrate the whole into a geometrical and, perhaps, cosmological pattern. We see the creation of huge straight streets giving immense vistas in Baroque Rome. (Even London got St James's Square, but the City remained resistant to the new trends and still has most of its medieval street network.)
But there's a feeling that most of this town planning was done for the wealthy, or for the commune as a whole. It didn't touch the lives of the working class or even the middle classes, much.
Well in Nuremberg, it did. The 'Sieben Zeilen' were built for weavers in 1489, timber framed houses arranged on what looks like seven rungs of a ladder between two diverging streets. It's an early town planning grid and though the houses look vernacular medieval - you can imagine them in any medieval town - the placement is typically Renaissance.
And these are lovely, big houses, with plenty of light (important for weavers, of course) and space around them.
It reminds me a little of the weavers' houses in London's Spitalfields, tall Georgian houses with huge penthouse windows at the top to let in light for the looms. Here too the weavers weren't poor workers - they were moderately wealthy entrepreneurs.