# Mathspp Blog

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##### Counting mosaics with APL

This is a short article on how I quickly used APL to verify my combinatorics calculations.

##### Problem #049 – coin pyramid

Can you make the pyramid point the other way by moving only three coins?

##### Problem #048 – trick or treat

Can you help these kids trick or treat their entire neighbourhood in this Halloween special?

##### TIL #012 – At operator for matrix multiplication

Today I learned that Python 3.5+ supports the operator @ for matrix multiplication.

##### Problem #046 – triangle grid

Can you draw 4 triangles in this 5 by 5 grid, covering all dots?

##### TIL #007 – math.nextafter

Today I learned about the math.nextafter method.

##### Problem #045 – 1, 2, 3

Figure out the number I'm thinking of with a single question!

##### TIL #001 – ceiling division in Python

Today I learned how to do ceiling division in Python just with //.

##### Problem #044 – send more money

Can you solve this simple-looking arithmetic challenge?

##### Problem #043 – Rubik's cube scrambling

If I scramble a Rubik's cube for long enough, will it solve itself?

##### Problem #042 – mine captcha

Can you solve this little minesweeper puzzle?

##### Problem #041 – canyon crossing

It's night time and 4 friends need to cross a fragile bridge, but they only have one torch. What's the order in which they should cross?

##### Problem #040 – the dozen puzzle

Three friends are given three different numbers that add up to a dozen. Can you figure out everyone's numbers?

##### Problem #039 – rope timer

You have two magical ropes that you can set on fire and you need to count 45 minutes. How do you do it?

##### Problem #038 – bridges of Königsberg

You are on vacation and must find the most efficient way to cross all bridges. How will you do that?

##### Buffet of self-references

This article will twist and bend your mind a little bit, as we go over some interesting self-referential concepts and objects.

##### Problem #037 - game of coins

Alice and Bob sit across each other, ready for their game of coins. Who will emerge victorious?

##### Problem #036 - huge, tiny triangle

Can you find a really large triangle that is also really tiny?

##### Problem #035 – unknown coin sides

This is an algorithmic puzzle where you just have to turn some coins.

##### Neural networks fundamentals with Python – subtleties

In the fifth article of this short series we will be handling some subtleties that we overlooked in our experiment to classify handwritten digits from the MNIST dataset.