Pattern works with any yarn and hook size. It might even work with other low-flying crochet stitches besides front-loop slip stitch, such as back-loop slip stitch, single crochet (in both top loops or back loop only), or some Tunisian stitches.

This pattern is not for beginners of slip stitch crochet. It involves increasing or decreasing a stitch in every row. (The written pattern has more information about the skill level.)

If you’re new to slip stitch crochet, first try the newly free Slipster Slackscarf. After that, Slip Tectonics or Undaria would bring novices solidly up to speed for these hearts.

See issue #76 of Vashti’s Crochet Inspirations Newsletter: it’s about crocheting heart shapes, and how this side-to-side slip stitch approach to the heart shape came to be.

Advanced slip stitchers can use the graph in that issue, and the shaping methods of your choice. Moderately experienced slip stitchers should start with the written pattern, which is at my blog here.