Blind people could 'see' letters that scientists drew on their brains with electricity https://www.livescience.com/drawing-letters-on-the-brain.html by @NicolettaML for @LiveScience; sweeping a current across multiple electrodes to trace patterns onto the surface of the visual vortex and generate recognizable shapes

Dynamic stimulation of visual cortex produces form vision in sighted and blind humans https://www.cell.com/cell/fulltext/S0092-8674(20)30496-7 "Dynamic stimulation of visual cortex allows both sighted and blind subjects to recognize a variety of letter shapes without training and with high accuracy"

(image) Analogy with static and dynamic tactile stimulation with multiple probes.

A major functional problem with this approach of sweeping across electrodes is that it scales poorly to larger numbers of electrodes: scanning multiple contours starts taking too long for real-time wearable use in daily living.