An Open Tour 20x21 with Crossing Zigzags

This is a tour I have been trying to construct since before the closed examples previously shown. I have had difficulty connecting it up round the edges without spoiling the central pattern. The darker lines in the first diagram show the parts of the basic zigzag that have been preserved. The other paths across the zigzag can take various forms.

Zigzag pattern

20x21 Open Symmetric Tour

Here is a closed tour using a similar crossing zigzags plan that I constructed the next day. The connections round the edges worked out much more easily than for the open tour. 

Crossing Zigzags

I have emphasised the two moves through the centre point.