Kaleidoscope and the Charles Dickens trojan horse: Little Dorritt
In the Yellow episode, Hannah Kim (Tati Gabrielle) demonstrates her cunning abilities by breaking into one of Roger Salas (Rufus Sewell) competitor's vaults.
We see Hannah doing a little internet sleuthing on someone named Kate Soto (Amanda Figueroa). Her dating website profile shows her job title as SVP of Investments & Analytics at Dunne & Co. Bank. In her photo gallery, a collection of books sits on her desk in the background. We can see A Christmas Carol, David Copperfield, Great Expectations, Oliver Twist, and Hard Times - all authored by Charles Dickens. Several appear to be from the Penguin Clothbound Classics collection.
Around 1:25 into the Yellow episode, Hannah bumps into Kate at a coffee shop, "accidentally" dropping her book. Kate notices it's Little Dorritt by Charles Dickens, and a meaningful connection is made - or so Kate thinks.
Kate and Hannah's eyes affectionately meet again while they're at separate tables, so Kate joins Hannah, which leads to an evening date at a more upscale restaraunt where Hannah gives Little Dorritt to Kate. Little does she know, a camera is planted in the binding.
Kate goes to her office the next day, carrying her special book and beaming with infatuation. She places it on her desk with the others, and voila! Hannah is able to see the passcodes Kate enters on her keyboard and classified information on her screen, which allows her to break into the vault (with no actual "breaking" required).