Nintendo Crossover (任天堂 クロスオーバー, 1981)

While Nintendo's head of Research and Development Gunpei Yokoi was busy overseeing the roll-out of the Game & Watch silver and gold series, he still found time to create a follow-up to his very successful Ten Billion puzzle: the Nintendo Crossover (クロスオーバー).

Unlike the Ten Billion, which was sold in large numbers worldwide, only a small quantity of Crossover puzzles was produced, making it one of the more rare and sought-after Nintendo items from the toys and games era.

Nintendo Crossover (1981)

The Crossover was advertised using the phrase「偏光スクリーン」, which means 'Polarized Light Screen'. The official English sub-title was 'Polarized Light Puzzle'. Why this is, we will get to in a minute.

Crossover was released in 1981, in three color variants: green, red or purple. It cost the same as the Ten Billion puzzle: ¥1,000.

Television commercial for the Nintendo Crossover

The TV commercial for the Crossover shows the objective of this puzzle. With the sliders on the top, you move the tiles inside the crossover, which creates color patterns.

Move the tiles with the sliders, until they all have the same color

Each tile can swap between two colors. For the red color variant of Crossover, the two colors are red and white. The green and purple variants use green and white and purple and white, respectively. Well, in reality the white is more like grey, actually.

The bottom row was moved and one tile changed color, the others did not

As said, when the tiles move they can change color. At first glance, this seems to happen randomly: sometimes they change color, and sometimes they don't. It is quite puzzling and immediately intriguing.

Solved!

The Crossover puzzle was an original invention, and Nintendo applied for a patent. This was granted in 1983 (US patent 4,402,510).

US Patent for the Crossover, simply titled "Puzzle Toy"

The Crossover comes in a two-piece storage case.

Crossover with its storage case

The puzzle consist of twenty-four square titles, arranged inside the puzzle housing in a grid of four rows and four columns. The tiles are visible through the transparent top. The aim of the puzzle is to correctly arrange the grid of four by four tiles in the middle, so they all show the same color (in this case, red or white).

The Crossover has four vertical and four horizontal sliders

The two white sliders on the opposite ends of each row and column are attached to each others, so they move together. Using one of these sliders, you can move five tiles at the same time, in either a row or a column.

Bottom of the Crossover

When we turn the Crossover over, we see the Nintendo copyright message.

Now, let's take closer look at these colors changing tiles.

Third column from the left is moved up, and tiles change color.

In the starting position in the left image below, all tiles are colored red. In the middle image, we see how the entire second row changes to "white", when we move it to the left. Next, we move the second column up. As shown in the right image, the two bottom tiles change color, but the top two keep the same color.

Here is what happens when we move row #2 left and column #2 up

So, how does this work? The images in the patent document come in handy to explain this.

Schematic taken from the Crossover US Patent

The magic of the changing colors is all down to clever use of polarizing plastic sheets that filter out light waves in one direction: either vertically or horizontally.

On the inside of the transparent top of the puzzle (part 7a), small pieces of this polarizing plastic sheet are attached in a fixed position (parts 4), arranged in a pattern as shown below: alternating pieces that filter vertical or horizontally.

The inside of the Crossover top contains sixteen pieces of polarizing plastic sheet,
eight vertically polarizing and eight horizontal

Each of the twenty-four tiles in the puzzle (parts 1) also contains a piece of polarizing plastic (parts 5). These are also mixed, with eight filtering vertically and sixteen horizontally. As a result, when you look at the tiles, you are in effect looking through two layers of polarizing plastic sheet: one piece attached to the moving tiles, and one piece fixed at the top of the puzzle.

If the two layers are of the same polarizing type (either horizontal or vertical - 4x/5x and 4y/5y), light will shine through and you see the tile as white (greyish). If the two layers are of a different polarizing type (one of the vertical type and the other horizontal - 4y/5x and 4x/5y), the light is blocked, and you see the color (red, green or purple, depending on which variant of Crossover you have).

The polarizing pieces on the tiles (left) plus the fixed pieces on the puzzle top produce
the effect shown on the right: if the two layers

As an example, the particular arrangement of tiles with vertical and horizontal polarizing pieces as shown on the left-side of the diagram above produces the color effect as shown on the right. This is explained by the middle diagram. Here you see how the polarizing type of each of the tiles combines with the polarizing pieces fixed to the top of the puzzle. If they have the same polarization orientation (indicated by two bars that point in same direction) the tile will appear white. If they have a different polarization orientation (indicated by two bars that form a cross) the tile will appear colored.

Because of this mechanism, each tile can seemingly - as if by magic - either change or keep its color, when it is moved one position by sliding a row or column.

All three color variants of Crossover

The Crossover is a nice puzzle, and provides a real challenge. It can take quite a while to figure out. In case you want some help: a solution can be found on Jaap Scherphuis' puzzle site.

Three Nintendo puzzles: Challenge Dice, Crossover and Ten Billion

If you are interested in the other Nintendo puzzles, check out the posts on Fifteengame, the Challenge Dice and the Ten Billion.