In Super Mario World, there are several types of blocks. Some blocks appeared in previous Super Mario games, but the most of them are new or are changed. For example, the brown brick blocks have disappeared and are replaced by a yellow block with two eyes. In Super Mario Bros, it is said that they are people of the Mushroom Kingdom that were turned into blocks by Bowser.
Turn blocks
Yellow blocks are cubic-shaped, yellow blocks with two eyes. They're one meter (39.37 inch) high, they're one meter wide and one meter long. The main difference with the brick blocks of previous Super Mario games is that you can't break them by jumping against their underside. Instead of breaking, they'll start to spin and you can just jump through them. To break a yellow block, stand on it and do spin jump, then land on the yellow block while spin-jumping. To break yellow blocks with Yoshi, stand with Yoshi on a yellow block, then do a spin jump. You will dismount Yoshi, but you'll also do a spin jump. Land while spin-jumping and holding the button (in the SNES-version the A-button) on Yoshi. Keep holding the button and Yoshi will break the yellow blocks.
If there are enemies walking over a yellow block, you can defeat them very easily just by jumping against the block they're walking or flying over. Of course, you must stand under the block so that you can jump against the underside of the block.
Some yellow blocks have coins or an item (such as a Super Mushroom or a Fire Flower) inside them. Jumping against the underside of these blocks will pop the item out. Note that if you jump against the most left underside of those blocks, the item will start moving to the right, and if you jump against the most right underside of the block, the item will start moving to the left. After the item has come out of the block, the block will turn into a solid block.
There are also yellow blocks that will produce a long "wire" of coins if you jump against them. You can move the wire of coins in the direction that you want by just pressing the same direction on the + pad. The block stops producing coins after a few seconds or if the first coin hits an obstacle.
Used blocks
Used blocks are ? Blocks after they are hit. They have an angry expression. They can't be broken, although they can be turned into coins (and vice versa) for a short time. To do this, step on a blue P-switch (not the one in the blue switch palace, but a small switch that you can grab and take it with you). For a short period, you'll hear a timer and all of the solid blocks will turn into coins, but all coins that were in the same room before you pressed the switch will now turn into solid blocks, creating walls but sometimes also new paths for you. You can also combine this technique with a block that produces a "wire" of coins. Just hit the block first, then step on the switch and guide the blocks into the direction that you want.
Roulette blocks
Roulette blocks are translucent blocks with an item inside. The item inside the block changes every second. Jumping on the block from below, or spinning your cape onto it, will cause the item to come out, but it will continue to change. You can also eat the item out of the block without hitting it on a Yoshi.
? blocks
? blocks always contain items. It can be one or more coins, but it can also be any power-up, or a Green Yoshi (red, yellow, and blue ones are exclusive to the Star World). To get as much coins out of a ?-block, stand under it and start jumping very fast. When the block has no more items in it, it will turn into a Used block. You can't break ? blocks by spin-jumping on them. They sometimes appear if you press a P-switch, creating new paths for you. At the start of some courses is a Starman, if you grab it and then run you'll sometimes find another ?-block. Jumping against it while you're still invincible will sometimes pop a new Starman out of it. Grab it and run further, until you see another ?-block, repeating the trick, and so on.
!-blocks
!-blocks are very special blocks. There are 4 different types. !-blocks only appear after you've pressed the big !-switch with the same color in a Switch Palace. Until then, only the outlines of the !-block appear.
- If you hit the underside of a yellow !-block, a Super Mushroom will come out.
- If you hit the underside of a green !-block, a Cape Feather will come out.
- If you hit the underside of a blue or red !-block, nothing will come out.
Each !-block can prove useful as when activated can lead to secrets. They can also bridge gaps which make completing a level much easier.
Grab blocks
Grab blocks look like blue turn blocks, but can't be turned. However, as their name implies, they can be picked up. When picked up, they begin to flash different colors, and will eventually disappear after a short time. Like any other object that can be picked up, they can be thrown as well.
Note blocks
Note block are somewhat similar to jump pads, but note blocks can appear also off the ground, unlike jump pads. If you jump on them, you'll jump back up a little bit. If you press and then hold the jump button while jumping on a note block, you'll jump very high. Sometimes a item will come out, but never coins. Note blocks appeared for the first time in Super Mario Bros. 3. Note blocks can appear as gold or white. The gold ones let you jump way higher than the white ones.
Triangle Blocks
When you're playing with Mario or Luigi (without Yoshi) and you run toward a smiling block and run on it, you'll just walk up the wall! To make sure you don't fall of the wall, just keep running and you'll walk straight up, higher and higher.
If you're riding Yoshi, Triangle Blocks act if they're Jump Pads, so you'll bounce off, jumping pretty high.
Star blocks
Star blocks can give you one of two things, based on how many coins you collect in the level. You can get a coin (only one), but you can also get a precious 1-up. Collect 30 or more coins in the screen (i.e. without entering a pipe or a door) to get a 1-Up when you hit it. They don't appear very often, but there's one in Yoshi's Island 3 on the end of the stage. After you've jumped against them, they'll just turn into solid blocks.
Power blocks
Power blocks appear in some castles and in some courses too. You can control the ceiling or something else, such as the path of a moving platform with it with it. When you enter a room in a castle with a power block, the ceiling will usually come down. Just keep your head cool and run toward a power block, then hit the underside of it. The text on it will change, and so does the color of it. When you've hit it the ceiling will go back, but when it has reached its highest point, it will come down again, so hurry up if you don't want to get squeezed.
Message blocks
Message blocks are blocks that display a hint or another message when you hit the underside of them. The one in Yoshi's House is quite special, because the text will be different when you're on Yoshi and when you're not. There's not much more to be said about it, because they can't do anything else. They just display something, not more and not less.
Boo Buddies
Boo Buddies are very special Boos. They were created by the Boos to fool Mario and Luigi, since Boo Buddies can turn into solid blocks, so Mario and Luigi would think that they were surrounded just by ordinary blocks. When Mario or Luigi then watched in the other direction, Boo Buddies could grab them. The plan didn't work. Boo Buddies only helped you out of the ghost house, instead of keeping you in. The strategy to let Boo Buddies create a stair for you so you can just walk out of the ghosthouse: just walk away from the Boo Buddies, so that they'll follow you. If they have reached the place you want, just turn around and they'll turn into solid blocks.
Hidden blocks
Hidden blocks are blocks that are invisible. So you can't see them. But if you hit a hidden block, you'll stop moving. If you jump against the underside of it, something useful will always come out of the block. After being hit, hidden blocks turn into solid blocks.