Face knife. Similar plain knives were used in human sacrifice. The faces were added as a form of deification, then put in burial offerings.
Skull mask. Front part of human skull used, then "eyes" added using shell and pyrite. Some had knives of flint put in nasal and oral cavities. The perforations in this one were thought to be for inserting hair or something to represent hair as deities of underworld were characterized with curly hair on head.