Secret piano birthday cake

Tomorrow is a special family birthday day. I have spent the morning making the pilaf from Marie Claire Taste 101 and the bases for the special secret birthday cake I am making.
The plan is to make a tall, layered, 20cm chocolate cake, and to layer it with fudge icing. I have made the two chocolate cakes, but even with me and the oven thermometer working overtime, they still puffed less than desired. I am unimpressed. I have gone to Plan B: make two more (plain this time) cakes and layer them in between the choc cakes. This will give me a much higher cake. Sure, the bottom layer will get a bit squashed, but that's fine. I'll have to get up early tomorrow morning and whip up the butter cakes, and then I'll be able to do the decoration! I've got a couple of packets of Orchard icing, and I'm going to make a piano keyboard in black and white around the sides of the cake. Today's task was to colour half the icing black. Please don't ever attempt this. It was hell on earth. I was hoping to find Orchard chocolate icing at Woolies, but no go, so I bought some food colouring and hoped for the best. I covered a chopping board with baking paper as a shield, put on some rubber gloves (eventually went through three pairs), and went nuts. It took soooooo long. I used significant amounts of red, blue and green colouring, and used cocoa powder to absorb all the extra moisture, which also added brown to the colour mix. Four hundred hours later, the kitchen and me all splattered with blue colouring (there was a small incident when a bug flew in the window and startled me), kneading, kneading, kneading, pouring, powdering, adding, kneading, kneading...arrrgh.
Apparently the icing is now black. By the end of it I couldn't tell black from nearly-black, purple, brown, browny-purple, purpley-green, whatever. It's not BLACK black, but it's a very dark feral colour and it looks black against the white, which is all anyone cares about.
I wonder if it will colour everyone's mouth.
I'm going to make the keyboard round the sides, then just have plain white on the top. I got a black icing gel pen at the supermarket, and I'll draw on a treble clef, stave, and possible a birthday message on the top.
Now, it's just down to you, oven. Don't let me down...

***next day***

I slept in! Arrgh. I had to do the butter cakes this morning...they turned out fine, despite the oven being PARTICULARLY BAD today. I discovered that when you set the oven to 200 C, the floor measures 110 and the top shelf measures 185. All you bakers out there, shed a tear for me. And be amazed that I turned out the result that I did! SO...I made the butter cakes, I made the fudge filling for in between the cake layers, then I tried to assemble it, all in an hour, while getting ready. It was total madness. I rolled out the fondant for the top, and tht was really difficult. It kept sticking, smearing and smudging, and when I'd pick it up to try to drape it over the cake, it kept tearing. Calm, calm. Try again. Eventually the top went on. It had a few choc smudges on it from where I didn't realise it had touched the fudgy icing sides. No prob, cover that up with something later on. Roll out the strips, measuring carefully for the cake sides. Had to do that in two sections. Big problem when it turned out the cake was higher on one side than the other. No idea how that happened. Re-measure, cut. Lots of gaps, and oozing fudge, and mess. Cutting strips and patches of fondant to fill the holes, like Selley's No-More-Gaps for birthday cake. The white icing looked like Frankencake at this stage. I considered giving up. No, we push on. Onward, to victory!
Cut out the keys from the black/brown icing. This was much easier. Careful not to get cocoa powder on pristine yet wrinkly, buckled, patchy white surface. Used skewer to drag lines into icing to represent piano keys, glued black keys on white with more fudge. Wiped down the edges. Cut out some dark hearts to cover some splotchy bits on the top. Got black gel icing pen, drew treble clef, stave, notes and name of birthday girl. Got white icing gel, filled in some tiny gaps, tidied things up a little. Was feeling much better about it at this stage. Kitchen looks like bomb has hit it: icing sugar, bits of fondant and cocoa everywhere. Zoom into the shower, dressed and in the car with cake, pilaf, presents and emergency cake repair kit, only 30 minutes late. At the party I sprinked around some gold chocolate coins to represent wealth and prosperity in the year ahead. It was a total success, everyone congratulated me and it was pretty tasty, if I do say so myself.
Note for the future: do not attempt cake of this magnitude with 24 hours notice. Destroy oven. Do not sleep in. Panic less... it's only a cake, after all!