First column:   year   month .   Number of months
Repeat day codes every columns.   Entry padding em.  

202520252026202620262026
NovDecJanFebMarApr
      
Mo1MoMo
Tu2TuTu
We3We1We
Th41Th2Th
Fr52Fr3Fr
Sa163Sa4Sa
Su274Su115Su
      
Mo385Mo226Mo
Tu496Tu337Tu
We5107We448We
Th6118Th559Th
Fr7129Fr6610Fr
Sa81310Sa7711Sa
Su91411Su8812Su
      
Mo101512Mo9913Mo
Tu111613Tu101014Tu
We121714We111115We
Th131815Th121216Th
Fr141916Fr131317Fr
Sa152017Sa141418Sa
Su162118Su151519Su
      
Mo172219Mo161620Mo
Tu182320Tu171721Tu
We192421We181822We
Th202522Th191923Th
Fr212623Fr202024Fr
Sa222724Sa212125Sa
Su232825Su222226Su
      
Mo242926Mo232327Mo
Tu253027Tu242428Tu
We263128We252529We
Th2729Th262630Th
Fr2830Fr2727Fr
Sa2931Sa2828Sa
Su30Su29Su
      
MoMo30Mo
TuTu31Tu

37 rows

Notes on curious non-bug on my home machine:
with date_default_timezone_set('UTC') - be patient
without that declaration