The 4" x 4" images were chosen as backgrounds for the 4x4 Arch Tunnel Book (with care to ensure the image seen through the smallest archway will be interesting).
The square images could be the cover of a 4x4 book, too. Plus extra images are included to use on any of the pages of the book (maybe sticking out a bit from the arch windows to see them when the book is closed).
Useful for other projects and ATCs, too.
This book is also included in the Tunnel Book Kit; see all the other kit components available to buy separately.190804-TnlBkKt 190804new