Signature Guide 4.0

A scratch redesign of [Makers Making Change](https://www.makersmakingchange.com/)'s [Signature Guide ](https://www.thingiverse.com/thing:3192347) in OpenSCAD with the following design objectives:

* conform to std credit card size ISO/IEC 7810 ID-1

* sign holes are tapered to reduce pen hangups

* corners of sign holes are very slightly rounded: this makes print less likely to lift from print bed

* one of the short edges has a very slight outward flare to help with removal from print bed

* one of the long edges has a slight bevel and is ruled in 10/5 millimetre ticks

* fairly easily customized in OpenSCAD.

Thanks to [Peter Lau](https://www.thingiverse.com/makerwiz/about) of [Makerwiz](https://makerwiz.com/) for donating colorFabb nGen filament used to print these to [Makers Making Change](https://www.makersmakingchange.com/).