The clover is the preferred design of MakeMasks2020.org (No affiliation but lots of admiration.) This pattern combines the best elements of several popular Covid19 Masks
including pleats, nose shaping, and a filter pocket.
Cotton T-Shirt or Tightly Woven Cotton Cloth
Bias Tape or Elastic
Flexible metal for nose clip
Assembly instructions are maintained in a google doc by MakeMasks.