Inside

Finished! We'll have to compare notes tomorrow to see if I did it the right way.

Spoiler

I didn't use R for anything.

This is probably the biggest level on Mekorama! At least the QR code is the densest that I have seen. Quite the involved level - lots to explore! It might be daunting for some, and I did have a bit of trouble poking into the holes on the sides. Here are some more observations:

Spoiler: Observations

- At first I didn't know what to do so I naturally pulled on all the draggables to see what would happen. This brought R up to the top and ruined that surprise you intended for me.

- With R in play, I then tried to get him to do the work of B, but he didn't want to fall off to the places needed. A bit of a waste of time, but now I know that R bots don't have all the same powers of B.

- The play after activation of the "taxi" is somewhere where improvement could be made. Getting B onto the taxi is possible from tapping in two different locations (inside from either of the two double-height windows) and there should probably be only one option.

- The fact that B always comes up upside down (in hover mode I believe) is probably a coincidence, but it has the effect that he get's spit out and off the tower if you don't make him get on his feet first. Kinda of a neat step to solving the puzzle, but some may get upset by it.

- If it is intentional (and it may be because I don't see another way down from the rim around the big opening) then WOW! I'm curious what you got going on there inside the tower.

- My biggest frustration was to get almost to the end and then have B miss the final lift and require a re-start.

- I also don't understand the inclusion of the third lift (opposite the first) unless it is just as a diversion.

Again, because most of your genius work is hidden behind the scenes, I fear that others will not appreciate this level as much as they probably should. I for one, though, felt the warmth of all your thoughtful design details through the cold stone skin of this monstrous undertaking. Thank you!!

@TR O I think you guys are misunderstanding each other with the phrase "pop out" and "inside."

Spoiler: Confusion

TL;DR

Yes, the solution to this puzzle involves activating a device "inside" the contraption and having B ride it like a taxi to the top - like "popping out" with it.

"INSIDE" CONFUSION

I think the original confusion came from when, TR O, you asked: "Haha!the thing inside scares me. Is that[sic] possible to get inside?" When I first read this question I thought you were asking whether it is possible to get inside the contraption, but now I'm thinking you were probably asking whether it's possible to get inside the thing that is inside (the taxi). Mark69 answered, "I think you have to go inside if you want to finish the level" Meaning, yes, getting B inside the contraption and onto the taxi (and not just walking around the outside cavity) is part of the puzzle.

TR O, you then asked: "I mean get inside the thing and pop out with it." Because the words "the thing" was the title of the spoiler, it wasn't clear. One could have read this simply as "I mean get inside and pop out with it." Again I believe that I and Mark69 misunderstood your question as simply to ask whether B had to get inside the contraption, while you probably meant whether B had to get inside the taxi.

"POP OUT" CONFUSION

When Mark69 wrote: "You have to pop out with it if you want to reach the goal" I believe he meant that, yes, riding the taxi to the top is one step towards reaching the win block. I also believe here that using the words "pop out" was him just trying to repeat your words back to you.

IF I'M WRONG, MAYBE

When you (TR O) first used the phrase "pop out", you were probably referring to the fact that when B first surfaces at the top riding the taxi, he is upside down in hover mode - and if you do nothing, he ends up getting spit out (from the inside and) off the game space (usually). This more represents a popping out effect, but it ends the opportunity to get to the win block and thus requires a restart.

Instead of "popping out" and off the game space, there are three possible solutions to finish the game (that is, after successfully activating and getting on the taxi):

1. Keep restarting and replaying the game until B simply pops off the taxi and onto the roof of the contraption, and from here simply walk B to the final lift by the win block (it happens sometimes);

2. [As a controlled version of 1:] As B comes up in hover mode, tap somewhere on the taxi to get B to stand up straight and stop moving (and popping out). Then tap somewhere on the grey perimeter wall and watch B clearly miss and fall just beyond the wall from where he can simply walk to the final lift near the win block; or

3. [Which is more involved and likely the more intended solution, is to have B ride the taxi back down inside the contraption.] So again, when B comes up in hover mode, tap somewhere on the taxi one or two times to get him to stand up straight and stop moving. Then, when the taxi reaches the bottom (or at least the same elevation as when B was able to get on in the first place), you can tap near the third interior lift (the one beside a double-height window) to send B off the taxi. Once he's at this lift, have B ride this lift to the top and then walk him to the exterior lift by the win block.

Hope this helps clear things up!

@TR O Hmm... I'll try again:

Spoiler: Center

No, B cannot just get to the center for two reasons:
1. Because of the steep angles, there is no way to see inside the contraption and thus find a spot to tap on and send B to; and
2. Because there is also no natural path that can lead him there... Not until after the "taxi" is activated.

When the taxi is activated (and that means B is no longer on the bottom floor), there is a temporary path created from the place he falls down to to, for example, the stone block beside the wedge seen through the lower double height window. In fact you can actually see the edge of "taxi" through the gap made by the wedge if you're looking from the right angle (i.e. dead on).

So when the taxi is in this position (probably at its lowest position, B can be sent from the place he falls down to to this spot beside the wedge. Since the taxi is now activated, it will start to rise up again. And because B can't make it over to the spot beside the wedge fast enough, he gets taken up to the top riding the base of the taxi.

So, in a sense, yes, B did get to appear in the center! But there is no way to send him there directly.

Bonus material: If you want to get extra technical, there is a fault in the design that allows for B to fall down into the center underneath the taxi and then get crushed by it. This can happen if you send B to the spot by the wedge as the taxi is already rising back up - in other words, sending B to that spot at the last possible moment (before the path completed by the base of the taxi no longer exists). Since B needs to travel a bit to get to the base of the taxi, and now the taxi is already on its way up, B will miss it and end up falling into the space left by it. When the taxi comes back down, B will be in its path and you'll be able to hear how it is crushing B.