Flexible Mask (Valvy mod)

UPDATES
-APRIL 9/2020: I have added a file (parts.zip) with all the parts in different files for those who want to try printing the base first and the parts on top for a smooth finish (copy & paste gcode challenge). I have added the gcode which prints the base first and then the components on top. This code was created for the popular Ender 3 Pro (base_mask_challenge_v2.gcode)
-APRIL 10/2020: I have added a table that was obtained as a result of research about which material is better to use for filtration. Maybe this will be useful for you. In summary, is better to use part of a surgical mask as a filter. I have added a separator for the input valve, this new design allows the valve to close freely (when the air is coming out); otherwise, it will be always open.

SUMMARY
I have made some modifications to the original designs to cover my necessities. Due to the lack of mask. My design is oriented to take more advantage of the surgical mask, using them as filter material. In thi