There are two competing ideas on what New Jerusalem will look like: either a cube or a pyramid:
Both are right!
The shape is two equilateral pyramids and a cube.
The “four square” is the four squares of the cube, and then on the top is the “mountain” pyramid that is just as high – measuring the edge – as the city is length-wise and breadth-wise. That counts 9 sides, but everything about the city must involve the number 12.
Therefore you add the pyramid on the bottom and now it is exactly 12 sides and 12 edges!
That’s the proof that this is the correct shape!
Fringing the top of the cube is the 144 cubit high wall in which are the 12 pearly gates, 3 on each side.
The shape resembles a head which is appropriate because this is Christ’s throne and will be the “head” to the universe, which will be like God’s body.
The city lights up the universe so it is fitting that it is shaped like a hanging lamp or a lantern. I couldn’t find anything with the exact same shape, but here are some items that have a resemblance:
Revelation chapter 21:
“And he carried me away in the spirit to a great and high mountain, and shewed me that great city, the holy Jerusalem, descending out of heaven from God,
Having the glory of God: and her light was like unto a stone most precious, even like a jasper stone, clear as crystal;
And had a wall great and high, and had twelve gates, and at the gates twelve angels, and names written thereon, which are the names of the twelve tribes of the children of Israel:
On the east three gates; on the north three gates; on the south three gates; and on the west three gates.
And the wall of the city had twelve foundations, and in them the names of the twelve apostles of the Lamb.
And he that talked with me had a golden reed to measure the city, and the gates thereof, and the wall thereof.
And the city lieth foursquare, and the length is as large as the breadth: and he measured the city with the reed, twelve thousand furlongs. The length and the breadth and the height of it are equal.
And he measured the wall thereof, an hundred and forty and four cubits, according to the measure of a man, that is, of the angel.
And the building of the wall of it was of jasper: and the city was pure gold, like unto clear glass.
And the foundations of the wall of the city were garnished with all manner of precious stones. The first foundation was jasper; the second, sapphire; the third, a chalcedony; the fourth, an emerald;
The fifth, sardonyx; the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.
And the twelve gates were twelve pearls; every several gate was of one pearl: and the street of the city was pure gold, as it were transparent glass.
And I saw no temple therein: for the Lord God Almighty and the Lamb are the temple of it.
And the city had no need of the sun, neither of the moon, to shine in it: for the glory of God did lighten it, and the Lamb is the light thereof.
And the nations of them which are saved shall walk in the light of it: and the kings of the earth do bring their glory and honour into it.
And the gates of it shall not be shut at all by day: for there shall be no night there.
And they shall bring the glory and honour of the nations into it.
And there shall in no wise enter into it any thing that defileth, neither whatsoever worketh abomination, or maketh a lie: but they which are written in the Lamb’s book of life.”
UPDATE: THIS POST NEEDS TO BE UPDATED TO SHOW CORRECT SHAPE OF NEW JERUSALEM, SEE NEW POST HERE: https://mackquigley.wordpress.com/2018/06/12/shape-of-new-jerusalem-solved/
New Jerusalem is probably shaped like an octahedron = a double pyramid. The bottom half is the foundation made with 12 stones and the top half is a mountain as tall as the city is square, which is 12,000 furlongs. A furlong is 1/8th of a mile (8 = number of new beginnings), so that 1500 miles.
The 1500 mile high mountain requires a massive base but there is only 1500 square miles to fit in, meaning the shape must resemble a pyramid.
On the four sides of that pyramid will be where we live in mansions of glory, under the throne of God at the top of the mountain. The total surface area of the 4 sides of New Jerusalem totals over 7.2 million square miles, which is more surface area than any nation on earth.
There are 640 acres per square mile so the total acreage is about 4.6 billion acres.
“25 And Judah and Israel dwelt safely, every man under his vine and under his fig tree, from Dan even to Beer–sheba, all the days of Solomon.” 1 Kings 4:25
“19 He brought me forth also into a large place; he delivered me, because he delighted in me.” Psalms 18:19
“5 I called upon the LORD in distress: the LORD answered me, and set me in a large place.” Psalms 118:5
“16 And I have put my words in thy mouth, and I have covered thee in the shadow of mine hand, that I may plant the heavens, and lay the foundations of the earth, and say unto Zion, Thou art my people.” Isaiah 51:16
“13 Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.” 2 Peter 3:13
“1 I was glad when they said unto me, Let us go into the house of the LORD. 2 Our feet shall stand within thy gates, O Jerusalem. 3 Jerusalem is builded as a city that is compact together: 4 Whither the tribes go up, the tribes of the LORD, unto the testimony of Israel, to give thanks unto the name of the LORD. 5 For there are set thrones of judgment, the thrones of the house of David. 6 Pray for the peace of Jerusalem: they shall prosper that love thee. 7 Peace be within thy walls, and prosperity within thy palaces. 8 For my brethren and companions’ sakes, I will now say, Peace be within thee. 9 Because of the house of the LORD our God I will seek thy good.” Psalms 122:1-9
“25 For this Agar is mount Sinai in Arabia, and answereth to Jerusalem which now is, and is in bondage with her children. 26 But Jerusalem which is above is free, which is the mother of us all.” Galatians 4:25-26
“8 And their dead bodies shall lie in the street of the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified.” Revelation 11:8
“8 When thou art bidden of any man to a wedding, sit not down in the highest room; lest a more honourable man than thou be bidden of him; 9 And he that bade thee and him come and say to thee, Give this man place; and thou begin with shame to take the lowest room. 10 But when thou art bidden, go and sit down in the lowest room; that when he that bade thee cometh, he may say unto thee, Friend, go up higher: then shalt thou have worship in the presence of them that sit at meat with thee. 11 For whosoever exalteth himself shall be abased; and he that humbleth himself shall be exalted.” Luke 14:8-11
“12 And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be.” Revelation 22:12
“24 Knowing that of the Lord ye shall receive the reward of the inheritance: for ye serve the Lord Christ.” Colossians 3:24
“12 Rejoice, and be exceeding glad: for great is your reward in heaven: for so persecuted they the prophets which were before you.” Matthew 5:12
“19 ¶ Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal: 20 But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal: 21 For where your treasure is, there will your heart be also.” Matthew 6:19-21