File:Cross section of the unopened fruiting body of the New Zealand basket fungus (Ileodictyon cibarium), next to a ballpoint pen..JPG - Wikimedia Commons
When using a ballpoint pen you sometimes reach a patch of the paper where it just refuses to write but the pen still works perfectly when you try it on another part
![Cross section of Pilot Vanishing Point | Pilot vanishing point, Vanishing point, Writing instruments Cross section of Pilot Vanishing Point | Pilot vanishing point, Vanishing point, Writing instruments](https://i.pinimg.com/736x/83/cf/a5/83cfa5458f0a8ea6b02c84bed500689d--vanishing-point-cross-section.jpg)