Bake with the kids they said. It will be a sweet memorable experience they said 🙃🙃🙃. Oh the arguments on who gets to pour this and that. Oh the mess. So much mess 😨. Oh the sugar rush when they’re high in sugar 🙃. I’m bracing myself for lots of baking days to come for the cooler season. I finally had a chance to play around with my iPad Pro. My previous tablet was just too laggy and while I love how intuitive the Apple Pencil is, it’s taking me sometime to learn the shortcuts without my keyboard 🥲. Nonetheless, I’m eager to learn and I’m so excited to do more comics on parenthood. #bubzcomics #cutecomic #comic #baking #lindytsang #bubzvlogz #bakingwithkids #instagramvsreality

📜 [專欄新文章] Gas Efficient Card Drawing in Solidity

✍️ Ping Chen

📥 歡迎投稿： https://medium.com/taipei-ethereum-meetup #徵技術分享文 #使用心得 #教學文 #medium

Assign random numbers as the index of newly minted NFTs

Scenario

The fun of generative art NFT projects depends on randomness. The industry standard is “blind box”, where both the images’ serial number and the NFTs’ index are predetermined but will be shifted randomly when the selling period ends. (They call it “reveal”) This approach effectively solves the randomness issue. However, it also requires buyers to wait until the campaign terminates. What if buyers want to know the exact card right away? We’ll need a reliable onchain card drawing solution.

The creator of Astrogator🐊 isn’t a fan of blind boxes; instead, it thinks unpacking cards right after purchase is more interesting.

Spec

When initializing this NFT contract, the creator will determine the total supply of it. And there will be an iterable function that is randomly picking a number from the remaining pool. The number must be in range and must not collide with any existing ones.

Our top priority is accessibility/gas efficiency. Given that gas cost on Ethereum is damn high nowadays, we need an elegant algorithm to control gas expanse at an acceptable range.

Achieving robust randomness isn’t the primary goal here. We assume there’s no strong financial incentive to cheat, so the RNG isn’t specified. Implementers can bring their own source of randomness that they think is good enough.

Implementation

Overview

The implementation is pretty short and straightforward. Imagine there’s an array that contains all remaining(unsold) cards. When drawIndex() is called, it generates a (uniform) random seed to draw a card from the array, shortens the array, and returns the selected card.

Algorithm

Drawing X cards from a deck with the same X amount of cards is equal to shuffling the deck and dealing them sequentially. It’s not a surprise that our algorithm is similar to random shuffling, and the only difference is turning that classic algo into an interactive version.

A typical random shuffle looks like this: for an array with N elements, you randomly pick a number i in (0,N), swap array[0] and array[i], then choose another number i in (1,N), swap array[1] and array[i], and so on. Eventually, you’ll get a mathematically random array in O(N) time.

So, the concept of our random card dealing is the same. When a user mints a new card, the smart contract picks a number in the array as NFT index, then grabs a number from the tail to fill the vacancy, in order to keep the array continuous.

Tweak

Furthermore, as long as the space of the NFT index is known, we don’t need to declare/initialize an array(which is super gas-intensive). Instead, assume there’s such an array that the n-th element is n, we don’t actually initialize it (so it is an array only contains “0”) until the rule is broken.

For the convenience of explanation, let’s call that mapping cache. If cache[i] is empty, it should be interpreted as i instead of 0. On the other hand, when a number is chosen and used, we’ll need to fill it up with another unused number. An intuitive method is to pick a number from the end of the array, since the length of the array is going to decrease by 1.

By doing so, the gas cost in the worst-case scenario is bound to be constant.

Performance and limitation

Comparing with the normal ascending index NFT minting, our random NFT implementation requires two extra SSTORE and one extra SLOAD, which cost 12600 ~ 27600 (5000+20000+2600) excess gas per token minted.

Theoretically, any instantly generated onchain random number is vulnerable. We can restrict contract interaction to mitigate risk. The mitigation is far from perfect, but it is the tradeoff that we have to accept.

ping.eth

Gas Efficient Card Drawing in Solidity was originally published in Taipei Ethereum Meetup on Medium, where people are continuing the conversation by highlighting and responding to this story.

👏 歡迎轉載分享鼓掌

Now on Sale

https://takaya.zaiko.io/e/hanayuishi2021

Live streaming from Konkai-Komyoji Temple in Kyoto

Saturday, October 30, 2021

15:30 Start on fine weather
17:30 Start on rainy weather

Archive video will be available on Zaiko until 23:59, Wednesday 2/11/2021. (You can watch as many times as you want during this period)

NOTICE: *In case of raining, the performance starts at 17:30. You will receive an email from Zaiko if the time is changed on the day.

【Tickets】
2250yen (including 250yen for handling fee)
Available on Zaiko from 1 Oct (Fri) 10:00 - 3 Nov 21:00 (JST)
*You will need to register for a ZAIKO account to purchase tickets.

【Before Watch】
Register and watch guide
https://www.youtube.com/watch?v=BwDzQxC8vlE

☆Please refer to the support page on the ZAIKO website for information on how to watch the show and detailed settings.
https://zaiko.io/support
ーーーーーーーーーーーーーーーーーーーーーー
Tohru Yamasaki
President of T2Generation
Organizer of “TSUKENOKAI”. Tsukeuchi (tsuke percussionist) for Kabuki.Born in Kojima, Kurashiki City, Okayama Pref. on 28 February, 1969. Blood Type: B
1989: Joined in LIFE SOGOBUTAI Co.,Ltd. (formerly known as LIFE Bijutsusha Ltd.) located in Takamatsu City, Kagawa Pref. Autumn 1990: Moved to Tokyo.October 1992: Joined in Pacific Art Center Inc. after working freelance. Assigned to SHINBASHI ENBUJO (theater) to start a career as a tsukeuchi (tsuke percussionist). Since then, engaged in Kabuki performances in and outof Japan. August 2020: Resigned from Pacific Art Center Inc. Established T2Generation to start supporting cultural activities through tsukeuchi performance. Based on the career, trying various performances of art and culture by collaborating with others from different fields.
�Tsuke is one of the sound effects to emphasize the movements and power of the characters on the stage, which impresses the play more effectively. It is often used for the important scenes: when the main character is appearing on stage, changing his/her clothes, when the stage setting changes (stage elevator rises or a building collapses), and to highlight the effect of props.“Oto (sound) wo tsuke-ru” means “adding sound to the play”, which is the reason why it is called “tsuke”. The two wood blocks to make sounds are called “tsuke-uchi”. Tsukeuchi (tsuke percussionist) sits on the stage left (audience’s right side) where he makes sounds using tools, tsuke-ita (tsuke wood board)and tsuke-gi (two wood blocks).
WEBT2Generation https://t-yamasaki.wixsite.com/t2generation
TSUKENOKAI https://t-yamasaki.wixsite.com/tsukenokai

HANAYUISHI TAKAYA
TAKAYA, as known as HANAYUISHI, is an artist based inkyoto who combines floristry with art and fashion to create one-of-a kind headdresses. Takaya has invented and developed a technique of tying living plants like flowers.vegetables.fruits.twigs.plants and even taxidermy into hairs to make highly unique and ethereal works - as he describes as a “unity of human and nature.”
Takaya creates his works on the spot,choosing flowers to with cloth or personality of the person. It is an intuitive and spontaneous work that it is almost impossible to plan the design ahead since flowers are living things every bloom is different.every stems has its own line.There is beauty of working with living plants as opposed to dried plants - as if Takaya intensifies the energy of the living plants.the result of his stylings are so vibrant and memorable.
Takaya shows his work through photography and live performance.
Performances are often held in unique locations like Buddhis temples and museums in throughout Japan and Sweden. He has been featured in numerous publications and broadcasts around the world, including Daily Telegraph, Glamour Italia, Holland Herald, and NHK World TV.
Takaya also collaborates with Yumi Katsura, a well-known bridal fashion designer for Yumi Katsura Grand Collection.
http://www.takaya

KONKAI-KOMYOJI TEMPLE
https://www.kurodani.jp/en/

finally recorded what i eat in a day, every day is different as we know, but in general i eat a lot of vegetables and these are some easy and healthy meals that we some times like to do!
should i do a week worth of what i eat in a day?
Love Laura 💕

See the daily updates here
▹Instagram - http://instagram.com/lauraribeiro.x

Time stamps
00:00 - intro
00:20 - breakfast
01:30 - lunch & learning about the gut
05:20 - new kitchen items
06:35 - cat snacks
08:03 - snack time
08:30 - dinner
11:15 - tea for dinner & netflix

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what I eat in a day in tokyo! 🥑🥒 easy healthy meals | japan diaries

歡迎大家回到我的food vlog🥰
雖然不再是"diet vlog"，因為健康的生活習慣不是一味的減脂，
而是平常多吃原型食物，偶爾吃一些你想吃的，無論「健不健康」

直覺式飲食就是可以回歸最基本，讓身體最直覺的感受去選擇食物，享受食物為我們帶來飽足感和學習如何控制飢餓感
直覺式飲食最重要的其實是增加運動量💪🏼

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會有更多健康又美味的食譜分享♡

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