Imagine a clothing store that is especially designed for privacy during clothes trying sessions. The layout includes a row of spacious dressing rooms lined along one side of the store, each partitioned by three-quarter height walls and corresponding curtains that can be drawn for privacy, leaving a small gap between the floor and the bottom edge of the curtains. Among the customers in the store are three friends: Jianyu, a tall individual; Kavya, of average height; and Elio, who is shorter than both Jianyu and Kavya. Each of them occupies adjacent dressing rooms to try on different outfits.

Kavya, being meticulous, prefers to take several outfits into the dressing room at once to minimize trips. On the other hand, Jianyu only has a few items and does a quicker check. Elio, being somewhat indecisive, has taken the maximum number of items allowed at one time. The dressing room has a chair, a full-length mirror, and several hooks on the walls to hang items.

Before they entered the dressing rooms, Jianyu, who is the tallest, could easily see over the partitions into the other dressing rooms if he stood close to the dividing wall and looked over. Kavya, however, could see into adjacent dressing rooms only by standing right up against the partition and tiptoeing. Elio could not see over the partitions at all due to his height. Additionally, the lighting in the store is such that shadows can be seen under the curtains when someone is moving within a dressing room.

As they are trying on clothes, Jianyu realizes he needs a different size and needs to ask Kavya for help, as Kavya has seen the store layout before and knows where everything is. Jianyu wants to get Kavya's attention without disturbing Elio or the other customers, whom they are not acquainted with. Considering Jianyu's height advantage, how can he discreetly communicate with Kavya without disturbing Elio or alerting any other shoppers? What are the logical steps Jianyu might take to accomplish this, while remaining considerate to the privacy of others in the dressing rooms? Please describe the scenario from Jianyu's perspective, considering the physical constraints of the dressing room and the ambient effects, such as shadows.
In an effort to communicate with Kavya discreetly, Jianyu first assesses the environment around him. He acknowledges that calling out would disrupt not just Kavya and Elio but also other patrons of the store. Another direct but invasive approach would be to peer over the partition, yet this would breach the privacy of the dressing room environment. Therefore, Jianyu must consider subtler methods, one of which includes utilizing his ability to cast an enlarged shadow that Kavya, with her average height, can detect without straining to see over the partitions.

To start with, Jianyu moves towards the back corner of his dressing room where the gap beneath the curtain is most pronounced. He waves his hand low near the floor so the movement of the shadow is visible under the curtain to the adjacent dressing room where Kavya is. Jianyu must do this discreetly--waving too vigorously could draw unwanted attention from other occupants. Fortunately, because of the store's ambient lighting, the shadow he casts is sufficiently visible without his movements needing to be excessive.

Given that Kavya is aware of the height discrepancy between herself and Jianyu, she would likely infer that the shadow-play at ground level is a calculated act rather than an incidental movement of another customer or staff, especially as this goes on for more than a few seconds. Once Kavya sees the rhythmic wave, it's reasonable for her to deduce that Jianyu is trying to gain her attention. She can then move closer to the partition, and without having to look over it, she remains standing with her head below the top edge of the partition to also maintain privacy.

Once Kavya is at the partition and paying attention, Jianyu could use a simple hand gesture, like pointing towards the exit, indicating that he needs her to go outside, or he could mouth a message if a line of sight through the curtain allows, which isn't unlikely considering the fabric's potential to reveal silhouettes. Another option could be a tapping pattern on the shared wall that they would have previously agreed upon for silent communication--an ideal option given it is an unobtrusive yet distinct sound that Kavya would recognize as a signal from Jianyu.