Hand a few dominoes to a random person and they will most likely place them so far apart from each other that they only just manage to topple. Hardly anybody would leave as little space between the dominoes as shown on the photo - but that is actually the best way to set them up. At least that's the vast majority of domino-builders agree on nowadays. Most of the "veteran" domino-topplers (by which I mean the guys who started domino-building in the 70's and 80's, set the first world records etc.) have always recommended more space between the dominoes, usually one inch, arguing this required less work for the same result - dominoes will always travel one meter per second, no matter what distance you leave between them, so if you place them far apart from each other, you have to set up only about 30 dominoes instead of 60 to get a line that will topple for one second. Also, some builders prefer more space between the dominoes because in their eyes, it results in a more beautiful toppling effect.

Domino Day has changed this "doctrine". Now it's almost a matter of course (especially in Europe, not so much in the US) that the dominoes need to be placed as shown on the photo: the gap is as big as a domino is thick (about 0.3 inches). This has some advantages: It lowers the risk of failure on many techniques; you can place more dominoes on the same space (and many domino-builders have to cope with having big ideas, but tiny rooms); many techniques are only possible using this way of building.

When toppling, such a line doesn't have the "tok - tok - tok" sound and effect that you usually associate with falling dominoes; they rather push forward like a wave in a very smooth way. (This results in another advantage - the line physically has more power, a stronger momentum, so it can topple heavier things.)

Now in order to build lines as straight as possible, you use a tool for help: Due to a lucky coincidence, usual pieces of LEGO happen to be just slightly thicker than dominoes so that you can build a nice "template" for the dominoes, also called "fork".

With that help, you will not just build straighter lines than by hand, you'll also need less time. That is because you don't need to place one domino after another seperately, but can fill in ten or more dominoes in the template in one movement. There are several techniques on how to do that best. I explain the one I use in this video (there are English subtitles, click the CC button below the video):

Turns don't need much explanation. The dominoes should be placed closely to each other on the inside, but they shouldn't touch. In that case, if all of the dominoes touch, they might even fail to topple.

As a domino "newbie", you tend to underestimate the centrifugal force. I took six years in my case until it finally dawned on me that seven dominoes are not sufficiant for a safe turn of 180 degrees. You can argue about how many dominoes such a turn does need to topple with 100% safety. I now put six dominoes into a turn of 90 degrees when I have only little space available; when I have more, I use seven or eight. That only refers to Lamping dominoes though; "Domino Express" and other kinds of dominoes tend to falling more "randomly" and need more dominoes, especially in 180-degree-turns, to fall safely.

The "professional" technique introduced at Domino Day for turns wants you to use twelve (!) dominoes for a turn of 90 degrees though - which is clearly more than necessary, but considering that a failing turn in the main line of Domino Day would be a disaster and that many of the builders come to Domino Day with no experience as domino-builders whatsoever, you can understand that they are taught a more-than-secure method.

The first step is to determine where the turn will end by laying down a right angle, as shown by the white dominoes here.

Afterwards, you fill in the resulting gap with ten dominoes.

And then just build the outer turn alongside to it. It has fourteen dominoes in total.

Of course that right angle trick works with just one turn, too, but as professional events such as Domino Day and CDT (we use this turn technique there as well) usually have double lines, I illustrated it with such a double line here.

The two blocks of three dominoes before and after the turn have the purpose of synchronizing the two lines so that they are "in lockstep". If the line on the inside reached the turn before the line on the outside, it could (with very bad luck...) fall into the outer line and topple it into the wrong direction. The block after the turn is necessary for the lockstep because the inner line will of course need less time to topple than the outer one, although just very slightly. But at Domino Day, they pay attention to these things...

Yes, the techniques that seem to be the most simple ones can sometimes be particularly complex ;-)

Fields are by far the most important project technique. It gets a bit boring though when it's the only technique you use, like some domino-builders unfortunately do. But no project of considerable size is complete without a field in it.

Surprise of surprises, a field is nothing but several lines next to each other, forming words or a picture.

You should avoid placing the lines so close to each other that they touch while falling; the effect is more beautiful if every line falls seperately. If you have really straight lines (and use Lamping dominoes), a gap of two millimeters is already enough to ensure that though. Most sensible is a gap of eight millimeters, I will explain later why.

Planning fields with detailed images will be explained on the next page; let's just start with the most basic pattern here to show what such plans generally look like. On this grid, two squares represent one domino (so the letters have a height of five dominoes, not ten as you might think).

After a while, you'll know these letters by heart and won't need a plan to build them.

You should always add at least one blank line on top and below of an image so that it has sort of a frame.

This is the most common way to topple a field. The photo shows a so-call field toppler (surprise, surprise): a barrier made out of solid glass. Two metal devices are taped to the ground and the the field toppler leans against it.

The advantage of this technique is that it has bascially a 100% reliability (unless you set it up completely wrong, how could it possibly fail?), and that unlike the technique shown below, it makes all the lines topple at exactly the same time, which can be a nice effect.

Funnily, I never use this technique - I like toppling everything only with dominoes, and am simply too lazy to buy or make one of these tools when I can just as well use dominoes for it.

Apart from the field toppler, this technique is the most secure one. It doesn't have a common name yet.

This is my favourite technique, because it has the most beautiful toppling effect among the secure toppling techniques. It looks like a wave going through the field.

Make sure that the dominoes are placed in an angle of 45 degrees to the field. If it's much more than that, the line might just fall alongside the field without toppling it, if it is much less, the dominoes might block each other.

This technique ist used a bit more frequently - although it isn't quite as reliable if you ask me. It can happen that one or two lines are not triggered, and it just looks terrible when a big field topples in one movement, but one or two lines are still standing. So I really prefer the other techniques. This one doesn't have a name either by the way - which is still an issue with many tricks: when talking to other domino-builders, you need to describe many techniques instead of being able to just use a term.

First step...

Second step...

Third step - like the first one again...

Fourth step - usually NOT like the first one. The dominoes are placed on the opposite site now compared to the first step.

So then you either have a wall...

...or, by building all stories that are possible with this length of the bottom layer, a 2D pyramid.

It's actually even more simple then walls - just two steps being repeated over and over. Pay attention to this basic level though. It needs to be very precisely accurate, otherwise you will get in trouble in the upper layers.

The second step is basically the first one mirrored...

...and so on.

Just like 2D pyramids and walls, 3D pyramids can be toppled simply with a normal line. And just like them, they need at least seven stories to topple reliably.

Speaking of stories - usually that's not how you name the size of a pyramid. Instead, you use the length and width of the bottom layer, so 5x5 for the pyramid on the picture.