1. Prepare the rice according to your rice cooker's instructions.
2. Once the rice is done, let the rice set in for about 10 mins. Transfer the rice to the medium bowl, and pour sushi vinegar or powder over the rice. Slice mix the rice with a rice paddle gently to combine vinegar and rice well and let it cool down.
3. In a small cup, add 80g sushi rice, scrambled egg, mayonnaise and curry powder and mix well.
4. In another small cup, add 100g sushi rice, chopped ham and mayonnaise and mix well.
5. In another small cup, add 100g sushi rice, aonori, broccoli powder(optional) and mayonnaise and mix well.
6. In another small cup, add 100g sushi rice, black sesame and soy sauce and mix well.
7. Line the pound cake tin with saran (plastic) wrap. Line the raw ham on the bottom of the pound cake tin, and add all colors rices in layers. Starting with the yellow rice. Put the slice cheese if desired on top of the yellow rice. Then add pink rice, green rice and black rice at the end. Press hard each layers from the top to pack the rice in tightly.
8. Chill the sushi cake about for 1 hour in the fridge before serving. Garnish with cherry tomatoes if desired.