Room 6: Starting to get tricky!

First visit (when entering through the lower red door)
Kill the worms with the wooden boxes. Push the upper wooden box back to the left on the field left to the hole. Push the spike on the far right one step left one up. Push the lower wooden box to the right until it is over the rightmost hole.

Then push the wooden box and the spike in the lower part of the room to the right. 

Push the spike on the conveyor belt, then the wooden box. To get the heart push the rightmost white block of the upper wall of the mini room down.

Now push the wooden box at the end of the conveyor belt up and to the left into the hole.

Fill the leftmost hole, first with the two spikes, then with the remaining wooden box. Take the fruits and the gems and leave to the red door on the left. Now, we go to room 7

Second visit (when entering through the purple door)
Wait in the door until the worm passes by and follow him to get the gem and the apples.