|
Grey is Odd |
Tips and Tricks: the double peninsula and the double gulf. The combination peninsula gulf and gulf peninsula
Let's consider the highlighted area. At the moment we cannot know what to put in place of the question marks but we can know if there will be two agreeing signs (dot, dot or cross, cross) or two discordant signs (dot, cross or cross, dot). The two highlighted areas are one even and one odd so since even + odd = odd we ask ourselves if column 2 is able to satisfy them. The answer is no as column 2 has only 2 dots so it will be necessary to insert a dot in one of the two peninsulas and a cross in the other peninsula. Since column 3 has 5 dots and since we know that the only cross of the column is in one of the two peninsulas, we can fill column 3 with dots excluding the two peninsulas.
Let's consider the highlighted area and ask ourselves what to insert in place of the question mark. The area is made up of 2 even areas and 2 odd areas so as even + even + odd + odd = even therefore an even number of dots will be needed to satisfy the highlighted area. Since lines fifth and sixth can provide a total of 3 + 4 = 7 dots it means that instead of the question mark it will take a dot so with the contribution of the latter the highlighted area will obtain the required number of dots
What has been said in reference to the double peninsula or the double gulf is also applicable in the case of the simultaneous presence of a peninsula and a gulf.