Hidden treasure??

I ask my students to touch the two crosses when they play, so that they get a full finger articulation. One cross on the index finger for a full thumb articulation, and the cross on the palm is just a general reminder to pull their fingers right into their palm.
The lines on the fingers are an extra guide to act as a reminder for correct placement of finger on the string.... i.e. line up the harp string with the lines on the fingertips.
I also use an orange as a teaching aid.... I'll leave that as a teaser for another post!